Require OBLPN Asset Number by Customer

Summary:

We have a scenario where we require Asset Seal Nbrs to be assigned to all OBLPN for specific customers. Do we have an option to create a rule that would prevent a Ship Load Close unless each OBLPN has been assigned a Seal Nbr? The caveat being that this rule would only apply to Customer A and Customer C.

From my understanding the only option that I can find are load attributes from the REQD_FIELDS parameter but that doesn't meet the need.

Looking for any feedback that anyone else might have on this subject and if they might have a solution.