LONDON—New York-based brokerage Integro Ltd. said last week it is forming a new London-based international insurance and reinsurance unit and has hired three veteran facultative reinsurance executives from Guy Carpenter & Co. L.L.C. to help run it.

Julian Samengo-Turner and Ron Whyte, who formerly led Guy Carpenter's GCFac Worldwide unit, have joined Integro as managing principals to lead the worldwide operations of the new group. Guy Carpenter is Marsh & McLennan Cos. Inc.'s reinsurance brokerage.

In addition, Marcus Hopkins, previously head of Guy Carpenter's U.K. facultative reinsurance operations, has joined as a managing principal and will lead the unit's London operations.

Integro plans to offer international reinsurance, insurance and wholesale capabilities, including placement for independent brokers around the world as well as its international network of partners that help place global risks for large U.S. clients.

The new unit initially will run independently of its existing London-based retail brokerage, Integro Insurance Brokers Ltd., which Integro established in 2005 with the acquisition of Lloyd's of London brokerage Humphreys Haggas Sutton & Co. Ltd. However, the new unit most likely will merge with the retail unit eventually, Integro Chief Executive Officer Roger Egan said.

While the new unit is more "market facing," Integro's large global clients will benefit, especially from the technical expertise that will come with the additions of Messrs. Samengo-Turner, Whyte and Hopkins, Mr. Egan said.

"These three...are brilliant at structuring deals, even complex deals that require facultative reinsurance and all kinds of complicated layering schemes," Mr. Egan said. "They are absolutely amongst the world's best dealmakers, and that will help our North American clients who typically place business in U.S. markets, but also... into the London and Bermuda markets."

Mr. Egan said Integro plans to hire 50 to 60 people over the next year to staff its new unit. While most will be in London, it also will look to Asia, other parts of Europe and South America to round out its expertise.

"Once we build that out, we will have the world's marketplace...covered," Mr. Egan said.

He noted that Integro currently has a presence in Bermuda and Sweden in addition to London and across the United States.

Established in May 2005 by industry veterans Robert Clements, Mr. Egan and Peter Garvey, Integro has been concentrating on building its retail brokerage operations. The firm always intended to get into the reinsurance business, though, and "this opportunity was just too good to pass up," Mr. Egan said.