It's possible to do almost anything. This would require some SDK work, but probably wouldn't be as complicated as you would think; though it wouldn't be simple. If I were to want to do this, I would look at how resources are added to the map, ie track how they are loaded into CvInfos, and then where they are referenced in other objects. My guess would be that they are loaded into a CvPlot object (though I'm not sure); if this were the case it would be possible to add an atribute to a CvUnit object (the animal unit in question), that adds the resource to the CvPlot object the unit is on.