I have two sites and every site has their departments and every department has it's head department, but some department expanded in whole organization. 

For example, there is a Financial department that shared or expand in SITE A and SITE B. This department has a Head Department that exist in SITE A. 

Now I want to design a service catalog that need to approve head department. But because of that Financial Head Department exist in SITE A and not exist in SITE B, Financial Department in SITE B hasn't Head Department. Notice that Head Department user doesn't exist in SITE B. 

When Financial users department want to add service request, the approver that head department can't find by SDP and doesn't send approve notification. What should I do? Do you have any solutions?

Thanks