Cosmopolitan Housing Group has begun merger talks with The Riverside Group - which if successful would create one of England's largest housing associations.Cosmopolitan - which has reportedly been suffering from financial difficulties - has approached Riverside about the possibility of merging to create a joint stock of 68,000 homes.According to data supplied in August 2011 by the now defunct Tenant Services Authority, such a move would birth the second biggest HA in England, just behind Sanctua...