Suggestion:
Replace 'Vendor's Marketplace' forum with 'NAXJA Sponsors' forum.
Remove 'Vendors Advertisements', 'Vendors Specials' and 'Vendors Give Aways', possibly also 'Feedback'
Create a new dedicated sub-forum for each Sponsor
Give the sponsor as many sponsor accounts as they need. Mark each account with a visible 'Gold Level Sponsor', 'Tin Level Sponsor' badge to match the sponsorship they are providing.
Create a dedicated sponsor sub-forum in 'NAXJA Sponsors' E.g. 'Clayton Offroad Manufacturing' as the sub-forum name, gives them instant recognition as a sponsor.
Only members and sponsors should be able to post in a Sponsor's sub-forum. Sponsors cannot post in each other's forums. Read only for everyone else.