Is there a way to make the field "Requisition BU" mandatory in manage receipts?

Summary:

Hello,

We would like to know if there is a way to make the field "Requisition BU" mandatory in the "Manage Receipts" tasks.

Content (please ensure you mask any confidential information):

When a user with the privilege "Create self-service all requisition receiving receipt" search a PO number to correct a receipt, in the search result, he has access to all the PO receipts, even those from BUs that he should not have access to.
We cannot remove this privilege neither, and the only way to restrict data to the BUs assigned to the user, would be to make the field "requisition BU" mandatory, since the LOV is limited to the BUs assigned to the user.