It can be written in GUI. If a hero buys and item and the hero is owned by player A but the hero is controlled by player B, then reduce the gold of player A buy the cost of the item and give the cost of the item gold back to player B. This might take making a few variables and using hashtables. Why don't you give it a try and post what you come up with? I don't really feel like trying it, but maybe someone nicer than me will do it.