Actually you should be able to use golden horde units in anothers army if you set the owner of the golden horde region to say france for example and then make the units buildable by the french, Cant remember the name of the region but its not on the map just in the text files, Hmm id say thats your best bet, Did you try this in the late game?

Ps this is just speculation

[This message has been edited by Swoosh So (edited 10-24-2002).]