To reach its large computing needs, the ALICE experiment at CERN has developed its own middleware called AliEn, centralised and relying on pilot jobs. One of its strength is the automatic installation of the required packages. The Nordic countries have offered a distributed Tier-1 centre for the CERN experiments, where the job management should be done with the NorduGrid middleware ARC.We have developed an interoperation module to allow to unify several computing sites using ARC, and make them look like a single site from the point of view of AliEn. A prototype has been completed and tested out of production. This talk will present implementation details of the system and its performance in tests.