Wow. That's a very good point.I agree with what @Ebeondi Asi said. And in addition, what happens when one leader decides to make trades without the consent of the others? Or a leader goes rogue and trades away needed goods for worthless ones? Not to mention that the trade ratios would have to be fixed by the game to avoid either taking advantage of other guilds, or basically transferring a guild Treasury in advance of a guild merge. I'm afraid it's a hard no from me.
It would be nice if one guild could trade goods from their treasury for goods from the treasury of another guild. This would make guild alliances much more important and encourage more fighting in both GVG and GBG.