The Blackstone Group is on the hunt to buy mortgage companies, including both lenders and servicers, according to industry advisors and others who have been briefed on the company’s plans. Blackstone, without disclosure, recently purchased Gateway Funding in Horsham, PA, and is in negotiations to buy PMAC Lending Services, sources contend. It also is talking to a company that goes by the name of Pinnacle, though there are several firms with that name, and at press time it was unclear which one. Observers describe...