If you don't feel like going through the motions of creating a script you can:
First: place a trigger in the corner of the map and name it 'crashTrig', give that trigger the parameters you want e.g. 'Condition: player in thisList - Activation: Blufor\Opfor etc.' - (This is for the find Helicopter task)
Second: Make a trigger set the A/B axis to '0' and make the condition '!alive *<heloName>' - (This is for the enemy attack position and getting the trigger to the helicopter)
Third: In the onActivation of the Second trigger put: *<name of enemy squad> doMove getPos <heloName>; crashTrig attachTo ["<heloName>",0,0,0]; (This will get your other trigger for finding the Helo attached to the crashed helo and get the enemy forces to move to the crashed Helicopter).
Edit: to name enemy squads just go into the init of the squad leader and put: *enmyGrp = group this;
*Put any name you want here