MHP was hired following a competitive pitch. The remit is to target Together’s investor, commercial, intermediary and consumer audiences.
The appointment follows the launch of a new brand identity at Together last September. The company, which was called Jerrold Holdings until last year, provides mortgages and other forms of finance. It also conducts property auctions.
The company provided loans totalling £971m in the 12 months to 31 March 2016.
Dee Gallagher, public relations manager at Together, said: "The business has traded successfully for more than four decades and is now really coming into its own as a leading specialist finance provider, so we look forward to working with MHP as we embark on the next exciting chapter of growth."