How to stop creating PO's from one specific legal entity

Summary:

Hi Team,
Business wants to stop creating PO from one specific legal entity.

for two orgs, business assigned one legal entity. We should stop creating PO's for that legal entity and organizations.

I made an org inactive still able to create a PO.

How can we control the same?

Thank You

Content (please ensure you mask any confidential information):

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):