Network appliance protocol.

I am developing a piece of equipment that I need to act as a network
appliance on a laboratory intranet. The device can only handle a single
user. In other words, once a user's PC finds it on the network, the user
will lock it up for his/her exclusive use, then release it when complete.

I'm assuming it will use DHCP to get an IP address, so the user computers
that will want to find it and use it won't have prior knowledge of its IP
address.

Is there some sort of existing broadcast/multicast protocol that is intended
for this kind of coordination between peers on an intranet?

Thanks,
Ed