Use of ApplicationID vs Profile attribute as a foreign key to a ClientID

[ANON]

I am looking for advice on usage of the ApplicationId
(aspnet_Applications table) to distinguish groups clients within the
same app. When I add a new client group I'd like to limit their view of
the system to just their own group. So calls to the Business & Data
Access layers will look for some client ID. Does it make sense to store
a client group ID fk (ie GUID) in the User's profile (aspnet_Profile
table) or use the Application ID that the user is defined to & create a
new application for each client group?

Hope this makes some sense - thanks in advance.

Regards,
DG