1) Add killed event handlers and have a side check ran in the script to see what side the killers are
2) Lock the vehicles anyway and have the killed event unlock the vehicle driver on event of being killed by the enemy
... Have each truck have a co driver, on the event of main driver being killed, then movindriver the co driver
3) Set up X amount of routes, and place empty markers for each waypoint position on that route, same number of markers as waypoints, same number of each per route
eg
;; lets call the convoy groupname "Convoy" for example purposes
and lets say that the convoy has 5 waypoints
?!(local server):exit
_markers = []
_route1 = ["r1a","r1b","r1c","r1d","r1e"]
_route2 = ["r2a","r2b","r2c","r2d","r2e"]
_route3 = ["r3a","r3b","r3c","r3d","r3e"]
_rnd = random 100
If (_rnd <33)then{_markers =_route1;goto "SETROUTE"}
If (_rnd <66)then{_markers =_route2;goto "SETROUTE"}
If (_rnd <100)then{_markers =_route;goto "SETROUTE"}
#SETROUTE
[Convoy,1]setwppos (getmarkerpos _markers select 0)
[Convoy,2]setwppos (getmarkerpos _markers select 1)
[Convoy,3]setwppos (getmarkerpos _markers select 2)
[Convoy,4]setwppos (getmarkerpos _markers select 3)
[Convoy,5]setwppos (getmarkerpos _markers select 4)
exit
All run server side only, seeing as its a fully qai controlled and manned group
Would be far better than a linear convoy route
Of course, a more elaborate scripting system can be produced, you could have just 1 move waypoint and when the convoy turns up at that waypoint, the waypoint runs a script which setposses it to the next _markers select X (using no delay in the script
That way you can have different number of "Artificial waypoints" per route
eg
Waypoint script
if(count tx_markers <= 0)then {tx_ConvoyEnd = true; Publicvariable "tx_ConvoyEnd"; exit}
_marker = tx_markers select 0
[group this,1] setWPpos (getmarkerpos_marker)
tx_markers = tx_markers - [_marker]
In addition, you could have an addaction attached to the Player commander, which basically allows the lockwp true or false for the onvoy, this way, if he finds a threat infront of him, he can halt the convoy, until the mines have been cleared etc
Good luck with your mission