We have an IPA that uses the existing Requesting Locations and their associated GL Accounting Units to route Invoice Payment Requests to the appropriate level approver. So basically, the IPA finds the Approver based off the Requesting Location value entered by the user in the highlighted free form user field (Req Loc For Acct Unit) below and routes accordingly.

I am looking for LPL assistance to change the ‘Req Loc For Acct Unit’ user defined field on the Request Invoice Payment Form from free form text to a search field to pull in all Requesting Locations.
There isn't a relation between the PayablesInvoice business class and RequestingLocations business class so I believe I would need to create one.
Can this be done?