Multiple Networks or some type of Firewall?

We have two clients that we are wanting to utilize Zero Tier for quick-fast RDP access, amongst other remote options. However, they are both have the same subnet,

We found out today that, while installing on their DC’s, the DHCP servers would conflict and shut down the DHCP service on one of the servers. We want access to each one of them, but do not necessarily want those machines to communicate. Does ZeroTier offer any sort of Firewall or a manageable way to handle this?

I have found a workaround since clients can be connected to multiple ZT networks. I have created two (one that connects my machines to that machine and another network connecting that machine to the backup server network (offsite) for nightly backups.)

Thanks in advance!

You should take a look at flow rules in ZeroTier. Coupled with tags they are incredibly powerful, you can get really granular control over your network traffic.
And the best thing is, it’s all available on free plan too (thank you ZeroTier).