I think I understand your problem.
I don't believe that X-cart has functionality built in to distinguish between wholesale and retail product types at this time.
I'm sure that something could be written in, perhaps using one of the param fields.
You could also create wholesale categories and set them as viewable to wholesale membership only. The existing products could use the wholesale categories as secondary categories that way any product not showing up in a wholesale category would not be viewable on login. I believe that this is how the membership functionality works.
Out of curiousity, why would you not want your wholesalers to see all of your product line? If they want to purchase it at your retail price, would you stop them?
Good Luck!
