GMAC Residential Holding Corp. is using salesforce.com to drive the growth of its GM Supplier Discount program for both car and home loans, as well as its GM Family First program. GMAC is one of several mortgage companies that are exploring new options in customer relationship management technologies. “Salesforce.com has been instrumental in helping us grow GMAC’s participation in General Motors Supplier Discount Program,” said Randy Rodriguez, vice president, GMAC Mortgage. “Securely housing GM's supplier information, as…