I was able to setup a webstore using virtuemart 2.0.18 and was able to create several users as vendors but I want to limit the display for this vendor for them to just see what products are assigned to them in the administrator product listing and would not able to see what other vendors are selling, how do I do this? I don't know if this was asked before but I was really having hard time searching how to do it properly cause eventually there will be a setup for multiple vendors and I don't want that all vendors can update any products even though it doesn't belong to them.
Probably you could try VM Vendor 3rd party custom extension.
Vendors who are Joomla superadmins can see and edit any product. Vendors who are Joomla admins can only edit their own products, but I don't know if thay can see other products in the BE. They can, of vourse, see all products in the front end anyway.