Couldn’t the existing server do this fairly easily by running multiple instances each pointing to a different directory for their content?
I guess the protocol might not like seeing multiple advertisements from the same IP address. But, you could use virtual NICs to create several IPs for the host, and bind each instance of the daemon to its own NIC / IP Address.
In linux this it’s easy to create virtual interfaces:
ifconfig eth0:1 192.168.2.11
ifconfig eth0:2 192.168.2.13
ifconfig eth0:3 192.168.2.17