I don't know if there's a way to do this inside the openvpn-bridge config, but this should also work:
Configure 192.168.1.1/24 as a new 'local' network on your home SME server, with the Router set to the 192.168.50.X ip address of the office SME server.
In /server-manager -
- select 'Local networks' on the left
- click 'Add Network'
- Network address: 192.168.1.0
- Subnet mask: 255.255.255.0
- Router address: 192.168.50.1 (assuming this is the LAN IP of the office SME server)
caveats -
* This won't work if you have 192.168.1.0/24 defined at home, too
* This assumes that the SME servers are the default gateways for both offices