I hoped you might... 😉
...but yes, it would be a very useful facility if it is possible to implement, I'm currently rolling 18Tb drives into the main 8 bay Synology NAS, the two five bay expansion chassis connected to it are getting the 10TB drives that were in the main unit rolled into them at the same time (along with a couple of new 10TB drives so that they both get a full set of five each). The old 4TB and 6TB drives would then ideally be rolled into (what will be) the HexOS NAS which currently consists of 500GB, 1TB and 2TB drives while I'm "playing" with it.