Hide groups tab for categories where groups creation is disabled or no groups

I need to hide the "Groups" tab in each category view where groups creation is not allowed and no groups are available.

I need this for this reason: I have a tree structure where main cat is only a voice but do not cointains groups, only sub-cats. So I don't want that the "Groups" tab is diplayed in this main category 'cause I don't have groups in this main cat.

Is there such feature (or can be implemented) without editing the override files?

No, no such feature exists. You'd need to edit the template files and check for group count then hide the tab if the category has no groups. There are no plans to implement such a feature.