The Obama Administration has been claiming that insurance companies will be competing for your dollars under the Affordable Care Act, but apparently they haven't surveyed the nation's top hospitals.

Americans who sign up for Obamacare will be getting a big surprise if they expect to access premium health care that may have been previously covered under their personal policies. Most of the top hospitals will accept insurance from just one or two companies operating under Obamacare.

"This doesn't surprise me," said Gail Wilensky, Medicare advisor for the second Bush Administration and senior fellow for Project HOPE. "There has been an incredible amount of focus on the premium cost and subsidy, and precious little focus on what you get for your money."

Regulations driven by the Obama White House have indeed made insurance more affordable – if, like Health and Human Services Secretary Kathleen Sebelius, you're looking only at price. But responding to Obamacare caps on premiums, many insurers will, in turn, simply offer top-tier doctors and hospitals far less cash for services rendered.

Watchdog.org looked at the top 18 hospitals nationwide as ranked by U.S. News and World Report for 2013-2014. We contacted each hospital to determine their contracts and talked to several insurance companies, as well.

The result of our investigation: Many top hospitals are simply opting out of Obamacare.

Chances are the individual plan you purchased outside Obamacare would allow you to go to these facilities. For example, fourth-ranked Cleveland Clinic accepts dozens of insurance plans if you buy one on your own. But go through Obamacare and you have just one choice: Medical Mutual of Ohio.

And that's not because their exchanges don't offer options. Both Ohio and California have a dozen insurance companies on their exchanges, yet two of the states' premier hospitals – Cleveland Clinic and Cedars-Sinai Medical Center – have only one company in their respective networks.

A few, like No. 1-rated Johns Hopkins in Maryland, are mandated under state law to accept all insurance companies. Other than that, the hospital with the largest number of insurance companies is University Hospitals Case Medical Center in Cleveland with just four. Fully 11 of the 18 hospitals had just one or two carriers.

"Many companies have selectively entered the exchanges because they are concerned that (the exchanges) will be dominated by risky, high-using populations who wanted insurance (before Obamacare) and couldn't afford it," said Wilsensky, who is also on the board of directors of UnitedHealth. "They are pressed to narrow their networks to stay within the premiums."

Consumers, too, will struggle with the new system. Many exchanges don't even list the insurance companies on their web sites. Some that do, like California, don't provide names of doctors or hospitals.

The price differences among hospitals "can be pretty profound," said Joe Mondy, spokesman for Cigna insurance. "When you are doing a cost comparison with doctors, you should look up the quality of the hospital as well. Hospital 'Y' could be great at pediatrics and not great at surgery."

Insurers operating in the exchanges are apparently hesitant to talk about the trade-off between price and quality. Two of the nation's largest insurers – Wellpoint and Aetna – refused to respond to a dozen calls and emails placed over the course of a week.

Wellpoint and Aetna's decision to not educate the public on its choices doesn't sit well with two experts.

"There is no reason to keep that quiet. It's not going to be a good secret for very long when people want to use the plans," Wilensky said.

"In many cases, consumers are shopping blind when it comes to what doctors and hospitals are included in their Obamacare exchange plans," said Josh Archambault, senior fellow with the think tank Foundation for Government Accountability. "These patients will be in for a rude awakening once they need care, and get stuck with a big bill for going out-of-network without realizing it."

All of this represents a larger problem with the Affordable Care Act, said Archambault, who has extensively studied the law.

"It reflects deeper issues in implementation," he said. "Some hospitals and doctors don't even know if they are in the network."

Just look at Seattle Children's Hospital, which ranks No. 11 on the U.S. News & World Report best pediatric hospital list. When Obamacare rolled out, the hospital found itself with just two out of seven insurance companies on Washington's exchange. The hospital sued the state's Office of Insurance on Oct. 4 for "failure to ensure adequate network coverage."

"Children's is the only pediatric hospital in King County and the preeminent provider of many pediatric specialty services in the Northwest," a hospital press release said. " Some of these specialized services not available elsewhere in our area or region include acute cancer care, level IV neonatal intensive care and heart, liver and intestinal transplantation."

And for doctors in Texas, "Basically, we don't know," said Stephen Brotherton, president of the Texas Medical Association. "We can't find out. At this point, it's part of the various unknowns with the marketplace. There are ways you can be on plans and not even realize it."