Housing association Carr-Gomm is to provide back-office functions including finance, HR and IT to the Alcohol Recovery Project under a five-year outsourcing contract.
The terms of the deal remain confidential, but Carr-Gomm said it will make a profit despite charging below the full commercial rates.
The London-based ARP is set to make savings of 8 per cent on its previous in-house arrangements.
The services, which range from handling invoices and recruiting staff to managing ARP's properties, will be carried out from Carr-Gomm's national office in London. Three ARP staff are transferring to Carr-Gomm, and at least one extra member of staff will be recruited. One compulsory redundancy will be made at ARP.
ARP chief executive Sally Scriminger said: "We chose Carr-Gomm because it showed a willingness to work with us as partners and was cost-effective.
This will enable us to focus on delivering high-quality services to the people we support."
Michael Stock, director of strategic resources at Carr-Gomm, said the deal could lead to other forms of joint working. "We hope to learn from ARP's expertise and gain the opportunity to work collaboratively," he said. "However, the contract only relates to the supply of central services.
We are not contractually committed to joint service delivery."
Carr-Gomm, which works with people with learning or physical disabilities and mental ill health, already provides consultancy and training to other charities and local authorities through a subsidiary, Consult Carr-Gomm, set up in 2002.
Chief executive Gary Lashko said: "This is an important step for us in expanding the services we offer to other charities as well as to individuals.
We are talking to other providers about similar link-ups."