Help on sharing a folder between two KVMs

I've been experimenting with KVMs this past week which means I'm very new to the topic, so bear with me if I'm talking nonsense.

So I have an old computer that I'm testing with. I've installed Proxmox as the host os and two linux KVMs on top of that. I'm wanting to share a folder between these two KVMs. I know a seperate disk drive would make this simpler, however I don't have a spare disk drive to work with. I took into consideration holding the files on one KVM and the other accessing the folder through the network, but I'm concerned about bogging down the system's bandwidth.

If you got a better idea or any input on what I've suggested, I would love to hear it.