Multimaster system & disconnected masters

We need a multimaster system that has (1 x MC43 and 1 x MD5) and (1 x MC43 & MD5) that exchange app in / out data when diagnostic and master bus is connected but continue to function with their own program using local IO when the systems are disconnected from each other. Each separate system has 1 x MC43 and 1 x MD5 display for viewing information inside the MC43. See system below showing the disconnection between the two separate systems:

The separate systems need to talk to each other using appin and appout, but still run separate control programs when disconnected.

Below is an extract from the IQAN user manual:

In this instance, I make the non headmaster optional in the settings so when the optional modules become disconnected from the headmaster, i get no errors in the headmaster and the headmaster. The headmaster continues to run its own application in a valid system state. 

In the optional module, when it disconnects from the headmaster, because the headmaster is not optional, will I get errors appear in system logs in addition to appin / appout for the timeout? I'm concerned it will log can bus module error state, the customer may be confused by these faults if it does this. Also this application will continue to run with its own local IO and control I have built into the application, so effectively becomes a standalone system that continues to run its logic even though its lost contact with the headmaster?

Any advice how I can handle the bus termination, as when we switch systems in and out, the bus configuration will change and we will loose termination at different points. Without the option to switch termination on and off unless the software is reloaded, I am unable to control this unless i switch relays on and off bringing in resistors at certain points on the bus. Maybe its easier to set up two separate applications that communicate when connected, can this be done with appin and appout in different application files?