Allow two pmOS installations on one device

I'm interested in being able to install two pmOS on one device; one sitting on the internal storage, the other on the SD card. For example, in combination with Tow-Boot, it would be really nice to be able to choose whether to boot into stable or edge pmOS via volume button (PinePhone Pro in my case).

As far as I have gathered, this is currently not possible as the pmOS root file system is selected based on the partition label, and when there's two installtions the conflicting (identical) label results in always the same installation being selected. I believe this is a known issue, but I'm not sure if it's tracked on here already.

I've tried myself on this issue with mixed success. I've modifed the init_functions.sh of the initramfs on the pmOS_boot paritions of my installtions to enforce specific root file systems to be selected based on their UUIDs, but no matter what I tried, I could either exclusively boot from internal storage or exclusively from SD card.

I'm trying to learn, so here's my naive understanding of the situation:

Altough even after I gave pmOS_root on the SD card an unique label and hardcoded that partition to always be selected by pmOS_boot of the SD card, the installtion on the eMMC would still somehow jump to the SD card. Any pointer would be appreciated. Or if there's a thread of people already working on this even better.