[Imp]

This is the best / only way to get some control over mech formations as both can be given seperate commands, the vehicles will still load infantry if they get to close however.

If you really want to try getting control but it effects rally split them into teams.
i.e 4 squad or vehicle platoon buy in 2 pairs of 2 by either making your own formations or assigning spare units to a redundant formation for deletion.

You can now do overwatch with them one pair moving only one hex one turn while the other moves further & vica versa.