MultiChain doesn't remember nodes by domain name, only by IP address.
So if your node IP addresses are constantly changing, you could run the risk of losing connections. I would say your best bet is to have one or two nodes with fixed IP addresses, which nodes will always find when they start up. Those fixed nodes can then ensure that all the other nodes find each other.
Your other option of course is to use addnode command to pass a hostname, or indeed the addnode runtime parameter (which can also be fixed in the multichain.conf file for that node).