Can anyone tell me how I can link certain products to specific customers, and only have these products show up when the customer logs in?   For example, I have products 1, 2, and 3, which everyone can see regardless of login or guest mode.  Then when customer A logs in, products 4, 5, and 6 are displayed only for that customer.   When customer B logs in, products 7, 8, and 9 are displayed only for that customer.   Can you point me in the right direction?  Can I use Customer Groups, or User Groups to accomplish this?  Thanks for any help on this.