Hi there,
I just answered your other post, but you've explained your use case here... the problem is the instances will need to be updated if the order changes. Do you only use your tilemap once per sprite collection? If so, there's an easy workaround - otherwise I can think of other ways to work around this, which may be easy to workaround.
There is also the scratchpad that allows you to draw a custom set of tiles / you can rearrange the tiles, but that may not work well enough in your instance.