Magento

Right now there is one “NOT LOGGED IN” customer group.  I have several different sites on the same magento instance.  I need to apply different tax rules for each site.  That means I need to be able to have a different customer group for each web site (in a different country).  As far as I can tell, there is no way to set the “guest account group” for an individual shop. 

Note: I have set this up for registered users just fine.  For now my solution is just to require registration of all customers. I"d like to allow guest checkout, so if anyone knows the solution to this issue that would be much appreciated.

Chris