How to create a SR for an instance belonging to a final customer

We have a special situation within our Service Dept and I don´t know how to create the workflow.

We sell equipment to our organization in the USA, and they sell that equipment to third party customers there. The instance begins its life belonging to our organization, then it gets installed on our organization in the USA (we still can see it) and then it gets sold to the final customer. At this moment the instance can be seen from the US installed base but we cannot see it from the Spain Installed Base.

The final customer, if they have problems, don´t contact the US office. They contact Spain and we generate the SR and the Repair Orders if needed. The relationship is always with the Spain Service Dept, never with the US.