I'm new to FF and the Miqo'te, so I'm still going through the larval "brain dump" stage. It seems to me that "tribe" (at the level of, say, the C tribe) encompasses a big enough population of Miqo'te that you'd almost have to have smaller divisions within it. Taking a guess way down at the small end of the scale, if there's a quarter of a million Mi'qote among the tribes, then each one would be about ten thousand. That's hundreds of breeding groups for each tribe.
Scottish clans have the idea of a sept, which can be considered to be a smaller subdivision of a clan, and made up of individual families. I'd imagine you'd see the same thing with Miqo'te: You'd have a tribe, which might be spread across a pretty big portion of the continent. Individual septs within the tribe would concentrate on a smaller area, or a village or two. Within the septs there'd be the individual breeding groups, as well as all the Tia from those groups.
Scottish clans have the idea of a sept, which can be considered to be a smaller subdivision of a clan, and made up of individual families. I'd imagine you'd see the same thing with Miqo'te: You'd have a tribe, which might be spread across a pretty big portion of the continent. Individual septs within the tribe would concentrate on a smaller area, or a village or two. Within the septs there'd be the individual breeding groups, as well as all the Tia from those groups.