Well bud,
You could probably make a script like this, name it setunitheight.sqs or something:
#Loop
~1
?(Alive _x): Goto "Loop";
~5.2 (change this to whatever your respawn delay is, (ex: respawndelay=15 this should be 15.2))
#setHeight
_x setpos [getpos _x select 0, getpos _x select 1, (getpos _x select 2) +100] (change the '+100' to a height that suites the mission, you will probably have to go through some trial and error)
Goto "Loop"
The Script without the '()' should look like this:
#Loop
~1
?(Alive _x): Goto "Loop"
~5.2
#setHeight
_x setpos [getpos _x select 0, getpos _x select 1, (getpos _x select 2) +100]
Goto "Loop"
If this doesn't do what you want just send me a private message and I'll write you another one ;D Hope everything works out for you.