The Blackstone Group this week finally completed its purchase of all or parts of PMAC Lending, a California-based lender that will help the investment banking firm establish itself in the red-hot West Coast mortgage market. Although the publicly traded Blackstone has maintained a cone of silence regarding its talks with PMAC, employees of the Chino Hills lender began reporting the news themselves through various social media outlets, including Facebook. At least two other nonbank lenders are in talks with Blackstone, one in California and one in Pennsylvania. A spokeswoman for Blackstone declined...