I'm trying to use VIPTrial to temp add players to chat groups. VIPTrial gives players temp usage of plugin permissions. Can BetterChat be set up to use permisson based system like "betterchat.vip/betterchat.mod" and so on to be able to add them to chat groups or is there another way of setting this up? 

Thanks,
Gen.

Better Chat does use a permissions-based/group system, it uses Oxide's permissions system for the backbone of it. Any "chat groups" in Better Chat are actually Oxide groups, so you can grant users access to those groups as you normally would with or without Better Chat.

I did reply to your other thread though: https://umod.org/community/timed-permissions/4575-adding-to-user-group