If you not automatically create channels from the working services, you can assign multiple services to a channel.
Then you can play with a timeout on getting a signal and priority. So, for my setup I set DVB-C as highest prio, as no streaming is required. If there is no stream coming in it switches to the next lower prio source (service) which is the IPTV backup.
Does this make sense to you ? You need to be in the expert view in config.