What type of USB device are you wanting to share with guests?
I can tell you there is no "perspective" to share "USB" devices with guests. Having said that. There maybe a possibility that some USB attached "drives" may show up as available for a local pass through connection. They will not be able to used as repos.
You probably better off using virtual box for such a connection. Probably on a windows host.
I hav had some success with a free Linux USB extender that allows you to present a USB device plugged in a Linux-based server host via TCP/IP network as a USB device on the Linux client.
I plugged miy Nokia phone usb cable in the server and the Nokia USB drive immediately shows up on the client desktop...
Also works for USB mouse/keyboard devices. You could compile it for your Linunx VMs