Trading in War? [Like in AOC]

Well guys,
Im making a map, and I'd like to be able to set up a way to have something similar to what we had in AOC

The trading system ;)


That is, I want players (between allies) to be able to send some unit to a building of an ally player and come back to a building of mine and get an amount of resources (gold, wood, etc).

I tried many ways, but all of them failed =(


Anyone here have any constructive idea?

Thanks.-

Is this really impossible?!

Please some trigger expert help me!

Variables to store data.
Store the player number, the gold wanted, and sum to trade in.
Send the player number a message saying "player number" wants "gold" for "sum".
Now, if he wants, simply type "agree" or something. Check if he has enough money, check if the other guy has enough gold. Then run the trade trigger.

Now, if you want them to be able to "collect" the trade. The trade trigger when on is like this.
Player (integer of player number) enters region
Give player gold.
Make sure you create this for all parties. try to make sure only one trade can be conducted at one time, and a new one can only be done after collection.

If this is confusing, simply do this.
STORE ALL VALUES. USE VALUES FOR TRADE.