How can I configure two openHAB instances to connect to the same Homematic CCU3

I have an openHAB 3 and an openHAB 4.0.0.M1 running in parallel, but I can only connect one of the bridges at the same time. Otherwise I get the following error:

**COMMUNICATION_ERROR** Jetty start failed

Both openHAB instances run on the same Synology Server in an individual Docker container with the same IP-Adress but different ports.

I guess I have to configure in the bridge configuration the following parameters but I don’t know how:
XML-RPC Callback Port
BIN-RPC Callback Port

Anyone has a solution for me here?
Thanks a lot

There is a binding to connect two openhab instances - my recommendation would be to only connect one instance to physical devices and than use that instance to expose the Thing’s via said binding to the second instance :thinking:

That would’nt help me much.
I try to reorganize my openHAB configuration with moving the functionally step-by-step von OH3 to OH4 instance in the next weeks.

Yes, I where using the binding in a similar way when upgrading from 2 to 3.
Exposing every physical devices via the first instance allowed me to implement my rules on the second instance (I did use that opportunity to switch from DSL Rules to Jython).

When I was done with the rules I started to transfer physical devices. And since the second instance was already aware of all physical devices - via the binding and the first instance - I only had to rewire the Things channels.

okay so thank you for this solution. I still would hope that it is possible to find an other way with changing the ports for these parameters at myold OH3 instance:
XML-RPC Callback Port
BIN-RPC Callback Port
Has anyone done that before?

@fex: Thank you for your solution. The binding is called remoteopenhab and is working fine for me.

Thanks a lot!