How to Separate locations for specific operating units?

Hi,

We want to know if is possible to have separate locations for a specific operating units.

For example, If we have Operating Unit A with locations A1, A2, A3. And Operating Unit B with location B1, B2, B3. Actually by functionality, the user can to choice location B1 for Operating Unit A, at the moment to create a purchase order or purchase requisitions (PO or iProcurement). So, we want to find the way to separate these locations and minimize user errors. In other words, that the user just can to choose locations, A1, A2, A3 for operating unit A, without have the possibility tho choice locations B1, B2 or B3 for operating unit A.