Ok Thank you for your ideas
I did the cycling owner thing of Tuxedo Templar but did not use the romanian implementation.
I don't want to use Wait since it freezes all other triggers...
I use 3 switches that determine which player owns the crystal.
Trigger1: Toggle Switch3 (preserve)
Trigger2: COND: Switch 3 is 0
ACTION:Toggle Switch2 (preserve)
Trigger3:COND: Switch 3 is 0
Switch 2 is 0
ACTION:Toggle Switch1 (preserve)
Trigger4:COND

witch 1 is 0
Switch 2 is 0
Switch 3 is 0
Player 1 commands at least 1 unit
ACTION:give crystal to Player1 (preserve)
Trigger5:COND: Switch 1 is 0
Switch 2 is 0
Switch 3 is 1
Player 2 commands at least 1 unit
ACTION:give crystal to Player2 (preserve)
and so on....
I use Hyper-Trigger too.
It works pretty well although the crystal disappears from time to time. When the crystal is held by a drone it remains invisible for other players but this is impossible to deal with i think.
Tell me what you think