How tu use a turncounter in triggeractions?

[primus360]

For example if you want a countdown in turns, which starts after a trigger (maybe entering a region or conquering a town) was executed.
You cannot handle this without having access to the game turncounter in direct way, because you do not know the turn the player will start the countdown.
Only having a condition with game turncounter is not enough to calculate for example three rounds time to fullfill a quest.
In my case i have buildt a 2 player non-coop near mirror map where each player has to conquer 4 hostile AI controled villages to be able to pass a gate.
If you pass the gate before your opponent, you should have advantages.
So there should spawn an additional unit for every turn for the faster player until the second player passes this gate too.
If you are faster, then you have to take more risk and so there should be a nice tactical balance.
This map really makes fun (playing against my wife - she is always the slow one ), but i have to make it simple and just spawn a fixed amount of units,
because i cannot access the turncounter.

And hey my wife and i are both professional software developers, maybe we both are thinking in the wrong way.