(CNN) As veteran Republican financiers prepared to rally behind Donald Trump they came with a condition: Don't use our money to reimburse yourself.

Trump appears to have agreed, and the presumptive GOP nominee and the Republican National Committee formalized an effort to raise $1 billion for what will likely be a bruising and expensive campaign against Hillary Clinton. Now some of the party's top money men are lending their expertise.

Trump announced a pair of joint fundraising agreements with the RNC late Tuesday. And three veteran GOP financiers -- Ron Weiser, a prominent fundraiser who previously directed cash to anti-Trump groups, Ray Washburne, a Dallas-based bundler who led fundraising for Chris Christie, and Elliott Broidy, a California venture capitalist -- will be the vice chairs for the new joint victory fund, multiple sources familiar with the plan tell CNN. A spokeswoman for the RNC said a full list of vice chairmen would be released in the coming days.

The new additions to the joint finance team, who hail from Trump's former rivals and even the #NeverTrump movement, are the latest indication that many of the party's prior standard-bearers are prepared to rally behind Trump -- and pitch in to help the GOP -- in spite of their reservations about the candidate.

It also continues the major change in Trump's position on fundraising. At nearly every rally this year, Trump has touted that he's self-funding his campaign (despite receiving millions from small donors and merchandising) as a sign of his independence from the political establishment and big donors.

Now, with less than six months to go until Election Day, Trump is racing to assemble a patchwork organization that can keep him competitive. To do so, he is largely flipping the traditional finance script. Rather than building an extensive party-steered finance network within the Trump campaign, Trump is building a modest operation within the RNC juggernaut.

JUST WATCHED A Trump transition Replay More Videos ... MUST WATCH A Trump transition 00:26

The trio's support came, in part, thanks to assurances from Trump that he would not use the dollars they raised to reimburse himself for the $36 million of his own fortune he has loaned his campaign committee, a Trump source said.

In private meetings, the new slate of vice chairmen made it clear to Trump and his staffers that they and other donors weren't interested in helping raise money to pay back the billionaire businessman, according to the Trump source. Trump has already lent his campaign committee $36 million and has promised to spend more on his efforts.

The donors want to see their money funneled into efforts, such as ramping up the ground organization, advertising and campaign travel. Trump says he will do just that.

JUST WATCHED Inside the thinking of Trump supporters Replay More Videos ... MUST WATCH Inside the thinking of Trump supporters 02:09

"I have absolutely no intention of paying myself back," Trump said in a statement Wednesday. "This money is a contribution made in order to 'Make America Great Again.'"

Nevertheless, should Trump change course and redirect those primary campaign checks to himself, donors would have little recourse.

"If he's going to pay himself back with that money there's nothing you can do to stop him," said Spencer Zwick, who ran Mitt Romney's finance team in 2012. "That, to me, seems like it might cause some concern."

How the Trump-RNC setup works

JUST WATCHED Trump blasts 'pathetic' new ad Replay More Videos ... MUST WATCH Trump blasts 'pathetic' new ad 01:58

Even with some professional fundraising help in his corner, Trump still starts general election fundraising so deep in a hole that several backers have abandoned all hope of going dollar-for-dollar with the big-money network assembled by Clinton. The pro-Clinton super PAC Priorities USA on Wednesday began anti-Trump advertising that will not subside until votes are cast in November.

Trump has mostly dabbled in fundraising to benefit others -- and will do so again Thursday at an event to benefit Christie, the New Jersey governor and former GOP presidential hopeful. Trump is not set to begin the battery of grip-and-grin functions that litter the presidential calendar until a finance event next Wednesday in Los Angeles.

To get started, the vice chairmen have divvied up regions of the country and are aiming to install finance chairs in each state, the Trump source said.

They all report to Lew Eisenberg, the RNC finance chair who is helming the victory committees. Donors will be able to gift nearly $450,000 to the committees, far larger checks than they were able to in 2012 in part because of changes to campaign finance laws.

Yet more than $300,000 of that will be funneled into party funds that cannot directly be spent on general election campaigns -- the building, convention and recount/legal funds.

Fundraisers note that Trump cannot stretch the boundaries here -- there are restrictions on how the earmarked money can be used. A building fund, for instance, can't be used to pay the salaries of field staffers in Ohio. But it is still a departure from traditional presidential fundraising, where Republican nominees collected money for their air or ground campaigns, and let super PACs -- not the RNC -- welcome the rest of the cash.

"We thought it was very important to raise money we could actually spend to put lead on the target," Zwick said.

Super PAC donors look for answers

Trump's super PACs, which can collect checks of unlimited size, are just forming, never mind landing major commitments. One GOP donor supporting Trump said "in a perfect world" Clinton would only outraise Trump by $400 million or $500 million.

"There's utter confusion. No one knows which is the right PAC to be affiliated with. No one understands how to deal with Trump," said another fundraiser, Yuri Vanetik, who signed onto the advisory board of Great America PAC. "I don't think he's really thought it through."

Ed Rollins, a prominent Republican hand who also joined Great America PAC, did not dispute that Trump boosters are starting deep in the hole.

"We're playing catch up," Rollins told supporters in a phone call Wednesday afternoon. "It's going to take a little extra effort to match their resources, but we're making every effort to get forward." Also on the call, former Texas Gov. Rick Perry, and one-time Trump critic, pitched the man who beat him to donors.

Donors, even those who have been paraded by these Trump super PACs as prominent backers, described on Wednesday a sense of bewilderment as they struggled to connect with the right aides or make forays into the right groups.

Ken Abramowitz, a Republican fundraiser who was promoted as a prominent Trump backer by one of the super PACs, the Committee for American Sovereignty, said things are only getting started. "I'm just in the first inning, trying to meet the key people."