Materials stored at plant 2 but owned by plant 1

Hello all,

I have a scenario that: My client is trading company, they have 2 branches in 2 cities. Each branch is defined as 1 plant in SAP system. There is case that sometimes they must store goods of branch A at branch B (goods still owned by branch A) and vice serva. How we can manage this scenario in SAP system? Should we create new storage location to manage? Currently they have 4 sloc: 3 for each product lines (consumer goods, mobile and electronics) and 1 for damage goods. Is it logical?

Thanks for any help/advice

Phong