The Torah says that the land was handed to two AND A HALF tribes (Num 32:33):
וַיִּתֵּן לָהֶם מֹשֶׁה לִבְנֵי־גָד וְלִבְנֵי רְאוּבֵן וְלַחֲצִי שֵׁבֶט מְנַשֶּׁה בֶן־יוֹסֵף אֶת־מַמְלֶכֶת סִיחֹן׃
So Moses assigned to them — to the Gadites, the Reubenites, and to the half-tribe of Manasseh son of Joseph—the kingdom of Sihon
I understand that a [whole] tribe was a legitimate unit for inheriting the lands, but not parts of it.
What kind of an Administrative unit "half the tribe" was? Was the tribe divided into two halves by families or number of people?
Could those lands be exchanged within the tribe between family's that got the land outside Israel and families inside Israel?