What would be the fastest way to find out if the current user is a member of some specific group?
The fastest way is to check user’s primary group. Each user has one primary group, which is identified by ID. (See TNTUserMan.UserInfo.PrimaryGroupID property). You may also obtain the list of all groups that the user is member of by using MemberOfGlob and MemberOfLocal properties. You may use TNTUserMan.LogonUserName property to determine the name of a logged on user. This name will include the name of the domain that the user belongs to: “DOMAINuser”.