I believe you could model this after a combination of long-term loan contracts and exhibition agreements. While the building hosting the exhibits are not museums, you could treat them as such in the contracts. The type of contract/agreement you would need would depend on how involved you want the hosting party to be. Who will be in charge of collections care? (i.e.periodic Condition Reports, environmental controls, etc) If some thing happens to an object, who will be liable? Are there security requirements involved?