You could do something like this (I'm assuming you want the jeep and truck to not be in the same group?)
Follow.sqs:
endwp=false
#LOOP
~1
[jeep1, 1] setWppos getpos truck
? !endwp: goto "LOOP"
This script basically attaches the jeep's waypoint to the truck, and then loops it every second.
To set this up, you need to give your jeep a 'move' waypoint, and synchronise it to a trigger (put 'endwp' in the condition field).
Whenever you want the following to stop, simply make 'endwp' true.
Hope this helps