TOTALLY LOVE the ability to bring in Pluto TV with M3U !!! And looking forward to adding more sources too. BUT it would be GREAT on the ANDROID / IOS apps to be able to sort the guide by SOURCE like you can on the web interface. With so many potential sources that can be added, being able to say ... I wanna see what is on "Pluto" or "Source 1" or "Source 2" in addition to the sports, favorites, news, etc.
KEEP UP THE GREAT WORK ... and would LOVE to see this feature 
I would like this too. Specifically, I like to discover movies to record over the next few days and the Search upcoming movies only looks at favorite channels. I don't want to have to make all the Pluto channels favorites to do this. I can select the Movies filter in Guide, but there are times that source would be handy.
The Web UI gives you the ability to select a specific set of channels by Source to view in the guide. Would love to see that in the Client implementations for Apple TV and Fire TV at a minimum
In my case with OTA, Xfinity channels via Prime, Pluto, Stirr, Locast and TV Everywhere the guide is incredibly long. Need a way to quickly subset it and a BY SOURCE would help immensely.
Thanks.
Have you looked into Channel Collections?
I wish the Source, Date and Time drop-lists at the top of the web UI Guide were also available on the clients.
I also wish there was a quick way to get back to a "home" position in the guide. Maybe sending the guide command while viewing the guide could reset to the home position.
I've looked at collections, but the process of setting them up when 100's of channels are at play is problematic. Picking channels to include in a collection is a one-at-a-time process. If it were possible to bring up a list of channels and then make multiple selections similar to source channel selections for favorites then it would be far more usable.
Well, after a 2nd look I see that YOU CAN select multiple channels. I still believe selecting on Source is a simpler approach, then use collections to subset source content.
My wife would lovecthis feature.
On client (nvidia shield) my wife constantly turns on/off sources.
I wish you could do it from the drop down menus in guide.