cb Autoactions : how to assign a groupjive group according to joomla usergroups

I would like to automatically include users in groupjive groups according to the usergroup joomla to which they are assigned.
Ex: when <user_id> is assigned to the acl group <group_joomla> it is automatically included in the groupjive group <groupjive_group_n>
Global settings: Category = groupjive, user = automatic, access: all
Tab condition: usergroups = <group_joomla> (the assigned joomla group)
Action tab = join groups -> <groupjive_group_n> (the group to join automatically)
Other tabs: none
What is the trigger to use? Should other variables or substitutions be added?

Trigger depends on where you want this to happen. Are you changing their usergroup strictly in backend by editing them in CB > User Management? You don't need a condition; just be sure to select <group_joomla> for the Access parameter.

ideally the assignment to the joomla group is done by a subscription component which assigns the joomla groups according to the subscription plan.
So it is according to these assignments that I have to include in one or the other groupjive group.

The group join needs to be done at the same time as your usergroup assignment. So if this for example is when a subscription is activated in CBSubs then you'd be acting on CBSubs triggers for that. Otherwise the best I can suggest is just do it after the user logs in using the onAfterLogin trigger.

CBSubs was my first choice but unfortunately the component does not offer the Stripe Connect plugin (payment one to many), so I have to choose another component (hikashop)

If hikashop fires a Joomla event on subscription activation then you can still act on that using CB Auto Actions. You'll just need to be sure CB Auto Actions Bot is installed and published then prefix the Joomla event in your auto action with joomla_ to act on it. Aside from that you can do something like suggested earlier and place them in the GJ group on onAfterLogin so that their next login will have to handle it.