Details of an alleged scheme by a state lawmaker accused by federal prosecutors of accepting more than $500,000 in exchange for lobbying activities point in the direction of the MediSys network as the hospital system that paid the lawmaker’s consulting firm, sources told The New York Sun.

Hospital executives told the Sun that a relationship among three hospital systems that was described in the criminal complaint against Assemblyman Anthony Seminerio of Queens matched a situation involving three systems in Queens and Nassau County.

The complaint against the assemblyman described two hospitals that were vying for ownership of a third hospital. Hospital systems said the scenario matches that of MediSys Health Network and North Shore Long Island Jewish Health System, which have been jockeying in recent months for ownership of Mary Immaculate Hospital in Jamaica and St. John’s Queens Hospital in Elmhurst, according to hospital executives.

North Shore said it had no financial dealings with Mr. Seminerio. A spokesman for MediSys declined to comment.

The complaint described an unidentified hospital that paid Mr. Seminerio nearly $400,000 so he would persuade the Assembly to overturn Governor Paterson’s proposed cuts to hospital funding and pave the way for business dealings by the hospital.

Law enforcement officials have not accused hospital executives of any criminal activity.

The MediSys network includes Brookdale University Hospital and Medical Center, Flushing Hospital Medical Center, and Jamaica Hospital Medical Center, which is in Mr. Seminerio’s district.

In the tight-knit hospital community in Queens, hospital executives said Mr. Seminerio is known as the “rabbi” of Jamaica Hospital, where he held a fund-raiser in March to celebrate three decades in office. Photographs of Mr. Seminerio embracing hospital executives — including the president and CEO of MediSys, David Rosen — were posted on the Web site of a local newspaper, the Queens Courier.

Executives interviewed by the Sun highlighted details in the complaint against Mr. Seminerio that they said were telling. In particular, they called attention to a June 20 conversation between Mr. Seminerio and a hospital executive in which they discuss the hospital’s acquisition of other hospitals.

Sources said the hospitals being sought were Mary Immaculate and St. John’s, two financially troubled facilities that previously were owned by Saint Vincent’s Catholic Medical Centers. Last year, the Catholic health system sold the hospitals to a newly formed corporation, Caritas, as part of its plan to emerge from bankruptcy. A spokeswoman for Caritas said it is seeking an affiliate to help finance operating costs, and she said in recent months more than one hospital has signaled interest in acquiring the two hospitals. Caritas executives declined to elaborate, citing confidentially agreements with the interested hospitals.

Representatives from North Shore, which has expressed interest in buying Caritas, denied a financial connection to Mr. Seminerio. “We were not the hospital executives that were being referred to,” a spokesman for the 15-hospital health network, Terry Lynam, said. Ole Pedersen, a spokesman for MediSys, which also had expressed interest in Caritas, said: “We have no comment that we’ll be providing.”

In the complaint, prosecutors also refer to the hospital implicated in the corruption as one “whose funding was substantially affected by the budget of the State of New York.” The financial impact on the three MediSys hospitals would have been $54 million, according to an analysis done by hospital industry groups and publicized during budget negotiations last month. Prosecutors also said a Medicaid-managed health care plan affiliated with the hospital paid $80,000 to Mr. Seminerio. MediSys runs such a health management organization, called Neighborhood Health Providers.

Following the arrest of Mr. Seminerio, hospital executives expressed dismay at how the relationship between the longtime lawmaker and hospitals played out. “Obviously, we’re concerned but not completely surprised,” the senior director of marketing at Mount Sinai Hospital of Queens, John Kump, said.

Some said any deal between the assemblyman and MediSys executives reflects the desperation felt in Queens, a medically underserved community, to keep hospitals financially afloat. “Clearly this situation is a reflection on how important health care is in Queens and how it has to be addressed,” Mr. Kump said.