Simplest way is to add another Channesl DVR server instance on your existing Synology NAS.
Install the Synology Docker package.
Install the Channels DVR Docker image and set it to use a different port, like 8189.
Also set it to use a different shared folder than the one you're currently using.
Your Channels DVR Server Synology package runs on port 8089.
The one in the docker container will run on port 8189 (or whatever port you choose).
I'm running 3 Channels DVR servers.
One in the Channels DVR Server Synology package.
The other two in docker containers.
They each point to their own recording and imports directories.