Controling Special Access via Usergroups - Is my way the correct way?

[peterska2]

If you just have one group, then use the primary usergroup changes.
If you have more than one group, use secondary usergroup changes.

After all, how can you be in more than one group if you can only change your primary one?

Using secondary groups means that the user has the best possible set of permissions from all the groups that they are a member of.