For a demo, go to <https://galene.org:8443/group/public/hn/>. Login twice in two different browser tabs (leave the password field empty). Click on the username of your partner, and choose Send file.
I opened a tab and signed in as "username".
Then I opened another tab and signed in as "username" there, too.
Thus a shared chat exists with two users named "username".
Whatever this is, it is not the path of disambiguation.
Transferring files shouldn't involve that central server, so you'd need to establish a direct connection between the users, and with network topologies those days, it will most likely require a relay between the two. It's not great.
That's exactly what Galene does when a user requests a file transfer.
> with network topologies those days, it will most likely require a relay between the two
We perform NAT traversal by using the server to punch holes in both NATs. Only if that fails (due to a symmetric NAT or to an overly restrictive firewall) do we fall back to relaying through the server.