Question on tunneling/bridging

[spynappels]

Hi All,

I have a question regarding a specific scenario I've been asked to resolve, and I'm not sure what's the best way to proceed.

Background:

A charity event which covers several buildings in a conference complex needs to have video streamed between buildings. All the video sender/receiver units and attendant IP phone system will be shipped to site preconfigured across a single subnet (we'll use 192.168.50.0 as an example).

Originally dedicated fibre lines would be made available between buildings to run network across (distances 200m+, no change of running new cables in), but now it appears that no dedicated fibre lines will be available.

We have the option of running 5GHz wireless bridges between buildings, but have also been offered the option to piggy-back on their existing network to send traffic between buildings.

I reckon I could set up P-t-P tunnels using OpenVPN, but I'm a little stumped on how I would deal with having different segments in the same subnet on either side of the tunnel. If they were different subnets either side I could set it up using routes, but obviously that's not an option in this case.

Unless I'm missing something, bridging tap interfaces won't work as the remote nodes won't connect directly to the VPN server.

Any ideas on where I should be looking?

Thanks for any pointers or guides you may be able to point me to.

TL,DR: Need to run one of the links between two sections of the same subnet across a tunnel, any ideas how?

[spynappels]

The thing is that I'm not having every client connect to the OpenVPN server, I have one client connected forming a tunnel between 2 buildings, with segments of the subnet on either side of the tunnel.