Tvheadend

Hi,

I have tvheadend 4.3 running on a PC on Ubuntu (current distro, tvheadend and kodi matrix 19.1).
DVB-C/C2 receiver is a AVM FritzBox Cable router with 4 dedicated DVB-C/C2 receivers builtin.
Pc and router are connected over GBit ethernet.
The DVB-C receivers of the fritzbox are integrated in tvheadend as DVBC-4 and always up and running.

Runs great, I can receive 4 TV streams at a time, eg. recording up to 3 different streams while watching one.
Switching channels without any delay... extreme cool.

So far, so good.
If all 4 receivers are already in use for recording, I naturally get the message "no adapter available" if I want wo watch TV.

Because of that, I added a second fritzfox with additional 4 DVB-C/C2 receivers and integrated it into tvheadend, also as DVBC-4.
So I have two independent fritzBox quad receivers active which equals to 8 receivers.
Works great as long as both quad receivers are up and running.

But... for power saving purposes, I turn the second FritzBox totally off if not needed.

Problem:
tvheadend (on the pc) does not automatically recognize if one of the quad receivers is temporarily not reachable over network.

I have to restart the tvheadend service to make tvheadend recognize the current setup (second quad receiver active or not).
Consequence of this restart is that all running recordings (via first quad receiver) are interrupted.

So here are my questions:
1. Is it possible to make tvheadend automatically do a frequent check / up-check if all receivers are available over network?
2. Or can I send a signal to tvheadend daemon to rescan receivers without interrupting current recordings?

Greetings from Germany
k-hm