hmm.. Gui ) Create 3 3 variables, one called UnitA, UnitB, UnitC, now set them to whatever youd like: next... Create a trigger and set event a unit is attacked and conditions attacking unit = unit A and attacked unit equal to C, now create a boolean variable called "BAttacked", then in that trigger you first created go to actions and do If BAttacked = true then // actions if unit B is attacked else // actions if unit B is not attacked
now last step....
create a trigger and a timer variable called TimerAttackB and in the new trigger set event A unit is attacked, condition if triggering unit equal to UnitB
then set the variable BAttacked = True and start the timer TimerAttackB as a non-periodiic timer that ends in 2-3 seconds (whichever number you prefer) and create the final trigger and set its event to TimerAttackB expires
and the action is set the variable BAttacked = False...
Phew. You better rep me for this!