The work around is to use Send to Location. If you send it to the location of the deck, it will end up the deck (Tim M pointed out this very useful fact to me and I’m using it in my module!)
You can also “nest” property references in a way to make this work.
If your player sides a Red and Blue (as an example) and the decks are named Red Gold and Blue Gold…
The location of Red Gold is stored in two dynamic properties, RedGoldX and RedGoldY, similarly for Blue. Then use a send to location, send it to x value $$PlayerSide$GoldX$ and y value $$PlayerSide$GoldX$. If you are playing Red, vassal will interpret this as $RedGoldX$ or $RedGoldY$ (or similar for Blue) and then will go on to interpret the coordinates you stored in the dynamic properties.