Hmm....
Try this:
Create the trigger where the Lieutenant comes trough.
Activation : Anybody
OnActivation : "_x playmove ""effectStandSalute""" foreach [Man1,Man2]
Repeatly
You might need to stop the units that salutes:
Man1 stop true
And set the correct dir:
Man1 setdir 0-359
And if anything else failes, disable the AI:
Man1 disableAI Move/Target/AutoTarget
Note : There is no sutch command as enableAI, so if it is disabled, it can never be enabled again.