Global Radio is to condense its 33 Heart stations into 15 regional broadcasting centres.
The stations will continue to broadcast networked content but will retain their own breakfast shows, drive-time shows and hourly news bulletins.
Crawley-based Mercury FM and Harlow-based Ten.17 will also join the Heart network, as part of Heart Sussex and Heart Essex respectively. Orion Media will retain its Nottingham-based Heart East Midlands station.
The 15 broadcasting centres will be: Heart West Midlands (Birmingham), Heart Sussex (Brighton), Heart West Country (Bristol) Heart Cambridgeshire (Peterborough), Heart Essex (Chelmsford), Heart Devon (Exeter), Heart South Coast (Fareham), Heart Gloucestershire (Gloucester), Heart Kent (Whitstable), Heart FM (London), Heart Home Counties (Milton Keynes), Heart East Anglia (Norwich), Heart Thames Valley (Reading), Heart Wiltshire (Swindon)and Heart North West & Wales (Wrexham).