COUNCIL BLUFFS, Iowa — The biggest donors in the Republican Party are financing a new group to recruit seasoned candidates and protect Senate incumbents from challenges by far-right conservatives and Tea Party enthusiasts who Republican leaders worry could complicate the party’s efforts to win control of the Senate.

The group, the Conservative Victory Project, is intended to counter other organizations that have helped defeat establishment Republican candidates over the last two election cycles. It is the most robust attempt yet by Republicans to impose a new sense of discipline on the party, particularly in primary races.

“There is a broad concern about having blown a significant number of races because the wrong candidates were selected,” said Steven J. Law, the president of American Crossroads, the “super PAC” creating the new project. “We don’t view ourselves as being in the incumbent protection business, but we want to pick the most conservative candidate who can win.”

The effort would put a new twist on the Republican-vs.-Republican warfare that has consumed the party’s primary races in recent years. In effect, the establishment is taking steps to fight back against Tea Party groups and other conservative organizations that have wielded significant influence in backing candidates who ultimately lost seats to Democrats in the general election.