Time Machine Mingling Catalina and Big Sur Backups

After installing Big Sur Beta 1, a Time Machine dialog popped up that I thought I ignored. Later I see that it backed up my iMac onto a volume called TimeMachine Backup (which is not the name of my main TM Backup so I felt this was fine).

Today I actually started to look at what was happening.

Big Sur renamed my TM Volume from the previous name to this "TimeMachine Backup" and has intermingled it's backup files with my previous Catalina ones.

Quick note about my setup. I'm running Catalina on a stock SSD in the iMac. I have a USB enclosure with 4 HDs in it. One of the 4 drives is dedicated to TM Backups. I partitioned that drive to install Big Sur onto. So I run Big Sur from a 100GB Partition on this 4TB drive.

Is there any way to:

• Break this intermingling or do I just erase the backup and have it start again from Catalina?

• Is TM smart enough to know which files belong to which backup OS? I booted into Catalina today and see that it thinks the most current backup is last week when the Mac last ran in Catalina, but I see backup files/folders dated today for the last 24 hours (for example).

• When I do break the intermingling I can leave Big Sur without a TM backup (it's just a testing partition anyway). But if I did want to test that feature, can I use the same TM drive and have it create it's own backup like it would if it was an external drive (I have backups on a Time Capsule that creates a separate folder for each Mac) or does TM consider this to be the "same" iMac as the the Catalina backup and thus the intermingling?

Thanks for any advice you might have.