There's also a thing Called IID. Can be quite useful at times. It's kind of like UID.
I don't know why the object properties is not showing this number, but if you check the debugger you can see that every object has an IID (instance ID) as well.
You can then use the System expression - Pick nth object. Then you can pick the specific object of that object type by IID instead.
So send the the object IID with the funciton then "pick nth object".
Maybe that could work as well?