Created an example for you that runs on a periodic timer so it will trigger as long as you have a baneling in each of the regions.
Trigger
Events
Timer - Every 5.0 seconds of Game Time
Local Variables
Conditions
(Unit type of (Unit 1 from (Baneling units in Region 001 owned by player (Triggering player) matching Excluded: Missile, Dead, Hidden, with at most Any Amount))) == Baneling
(Unit type of (Unit 1 from (Baneling units in Region 002 owned by player (Triggering player) matching Excluded: Missile, Dead, Hidden, with at most Any Amount))) == Baneling
Actions
Unit - Create 1 Mutalisk for player 1 at MutaliskSpawnPoint using default facing (No Options)
If you just want it to happen once for each time you bring a baneling into the regions you'll have to use a "unit enters/leaves region" event and switch out one of the conditions for a "unit type of triggering unit == baneling", and duplicate and edit the trigger so you'll have one trigger with conditions for each of the regions.
timed events are terrible NEVER use them they are NOT dependable on Battle net. and they will never work when you need them to if they error on battle net at all for any reason, battle net will disable it and your trigger will be useless. not to mention the lagg involded with everyone in the game having a timed event that goes off every .5 seconds.
timed events are terrible NEVER use them they are NOT dependable on Battle net. and they will never work when you need them to if they error on battle net at all for any reason, battle net will disable it and your trigger will be useless. not to mention the lagg involded with everyone in the game having a timed event that goes off every .5 seconds.
make the event:
when any unit enters region