All my raw editors can export a JPEG to the same location as the raw file. PM RAW+JPEG will only relate one JPEG to the raw because their {filenamebas} must match. Comparing edited image variants from one or from multiple raw editors means dealing with multiple JPEGs each typically having a common filenamebas plus a suffix like "-1", "-2", "-A", "-B" added by the editor application for uniqueness.
PM pairs "xyz_1234.jpg" with "xyz_1234.nef", but PM does not pair "xyz_1234-1.jpg" with "xyz_1234.nef". Depending on circumstances (such as contact sheet arrangement) I too often fail to see and select all JPEG variants manually. I envision a process like
1) Select an image/file in the open contact sheet
2) Press hotkey to bring up a "find family" dialog with the selected image {filenamebas} expanded in the input field with the cursor at end of the string.
3) Press Enter to run search and select
Selecting "xyz_1234.nef" in step one should select all files matching "xyz_1234*.*" meaning even the .nef.
If I happen to select xyz_1234-A1.jpg rather than xyz_1234.nef in step one, I would complete step two by pressing backspace three times to remove "-A1" from the end of the string. Step three would work as before, press Enter and have all "xyz_1234*.*" files selected in the contact sheet.
This would simplify my life with several JPGs per raw.
I know, chances are that Kirk will point me to the existing solution, an old and very elegant one, that I have ignorantly overlooked for so long.