Can we limit the users that are available in the Requester field on the Invoice Header level

We use the Requester field on the Invoice Header level to route invoices for some specific account, but this also creates the risk of internal fraud when users can select anyone (including themselves) in this field.

Is there a way to limit the users that can be selected in this field? Either by inclusion or exclusion would both work for us.

I thought of a workaround using the BPM rules to reject invoices that are assigned to ineligible users, but that is not a nice way to solve this requirement in my opinion.