Active Directory Integration (Loose Or Tight)

Dear All, 

i am new to Sophos XG firewall. we have been using Sophos web appliance since a while and we managed all our AD users in custom groups we made in Web appliance and assigned different policies to different groups. there are only 2 OU in AD which categorize almost 600 users in our environment.

we have also tried Cyberoam UTM (now acquired by Sophos), which has two options for authenticating with AD, "loose integration" & "tight integration". for the purpose of managing users in custom groups regardless of AD categorization, we must choose "loose integration".

i cant seems to find the "loose integration" option in XG firewall which means that i have to reorganize my web appliance user groups in AD.

what i wonder about is that: if there is no loose integration option available in XG firewall then what is the purpose of custom user groups.

Regards,

Faheem