You could do something like:
_resunits = [r_unit_0, r_unit_1, r_jeep_0, ..]
or
_resunits = units r_grp_0 + units r_grp_1 ... + [r_jeep_0]..
then do the same thing with eastern units, and have them in the same order, type-wise, i.e., first four soldiers, then a jeep, bla bla, in both arrays.
_eastunits = [e_unit_0, e_unit_1, e_jeep_0, ...]
(or the group thing).
Then go ahead and place all your resistance units with the editor around the city, and the east units out of sight somewhere else on the island.
And when you have faded out to black, do something like:
_i = 0
#loop
_ru = _resunits select _i
_eu = _eastunits select _i
_p = GetPos _ru
_ru SetPos GetMarkerPos "mrk_somewhereelse"
_eu SetPos _p
_i = _i + 1
? (_i < count _resunits): goto "loop"
This would effectively swap all resistance units for eastern ones in blink of an eye.
Waypoint/move-wise you'll have to come up with something.
You could assign one waypoint each for your resistance units and then
have the eastern counterpart walk there (inside the loop above) with
something like:
_eu Move GetWpPos [_ru, 1]
(Syntax might be slightly off)