[Pre-sales] Prevent user registration during checkout

-- HikaShop version -- : pre-sales
-- Joomla version -- : 3.3.6

I'm running a private invite-only Jomsocial community using invitex to manage invitations and registrations (users can only register in Joomla if they have been invited through invitex component).

The shop area, however, will be open to the public. Can hikashop allow a user to checkout either as a Guest or with a Login if the user already has a Joomla account? Basically, I want to make sure that users cannot create a Joomla account (and thus have access to the invite-only community) by just purchasing something in the store. I will be looking at the Hikashop Business Edition with Hikamarket.

Thanks.