Your best bet would be to install the LATEST version of Vicidial which is very close to being multi-tenant. Most items are now linked to user groups.
Beware: DO NOT ASSIGN YOURSELF TO A USER GROUP THAT HAS BEEN MODIFIED! Leave your user/user group alone. Create new ones. If you modify the user group for 6666, you'll probably lock yourself out. LOL
And I've not looked at the manual for this feature, nor has a client recently asked me about this function: Which leads me to believe that it's fairly straightforward. I've seen "user group" pop up on almost every menu slowly but surely, and I think it's on almost all (if not all) by now.
But this is in "Vicidial" latest version not in the old versions installed with the goautodial .iso.
Install with Vicibox 6.0.3 (from Vicibox.com) or later to get the latest version of Vicidial with the latest installation code, configuration, and packages. It's also easily upgradeable these days if you install that way.