Create Server to Server VPN to allow multicast

I have 2 dedicated server running fresh installation of debian. I want the freelancer to set up a way for those to server to communicate via mutlicast and to essentially be on the same private LAN. I assume you will achieve this via OpenVPN (or some sort of VPN solution) but I am open to ideas. Please send me a short proposal how you plan on achieving this, I will need at the end of the successful set up a set of instructions so I will be able to replicate the configs and installation on other servers in the future to add to this private LAN so they can all communicate via multicast