Source Filtering

From the web GUI when I am looking at the Guide and go to the Sources dropdown, I am noticing that when I select from a source it lists many more streams than what is part of that source.
Best I can gather is that many of my sources use the same guide data so they all appear.

For example when I select a source that is using X-M3U guide data, the guide lists any channel that is also using that regardless of whether that is actually part of the source or not.
However if I select my Pluto, Stirr, or MLB-TV as the source for the guide, they list only that stream as they each use their own EPG data.

Is there any way to actually filter on the sources instead of the EPG guide data?