Currently, there is a plugin when I create a time entry as a contract worker that checks whether the vendor linked to my bookable resource is the same vendor that is indicated on the subcontract that I fill in on my time entry.

This restricts the following

1. Suppose I work for VENDOR A
2. Project X is a project in COMPANY 100 for which a subcontract exists to VENDOR A in company 100
3. my bookable resource is linked to this vendor record in company 100
4. Project Y is a project in COMPANY 200 for which a subcontract exists to VENDOR A but this is a different vendor in COMPANY 200

I as a contract worker can NOT log time on the subcontract & project of COMPANY 200 as it is not the same vendor as indicated on my bookable resource

This makes it impossible for one vendor resource to work on projects from different legal entities. This can occur very often.

I would put this validation on the party instead of the vendor. This way, when I try to perform work on the project from COMPANY 200, the vendor associated to the subcontract in COMPANY 200, is the same party as the vendor in COMPANY 100. This would make it possible for one contract worker to work for projects across multiple legal entities.