Three Dorset districts are set to share staff and services in a full three-way partnership.
North Dorset DC has agreed a partnership with West Dorset DC, which is already in a sharing arrangement with Weymouth & Portland BC.
The latter is due to endorse the three-way deal on 6 November.
Deborah Croney (Con), North Dorset’s leader, said: “Today we made a landmark decision that will protect and improve services for the future providing an unlimited number of opportunities that will be of great benefit to residents.”
Matt Prosser (pictured) is already shared chief executive of West Dorset and Weymouth & Portland and is expected to take over at North Dorset, where chief executive Liz Goodall is due to retire by March 2015.
The councils have said that sharing could see some £6m saved by 2019-20, mainly from more efficient use of accommodation.
Dorset’s other three districts attempted a similar three-way share in November 2013. This collapsed when Purbeck DC decided against joining the existing partnership of Christchurch BC and East Dorset DC.