Insert "-" after capitals

[mp3renamer]

I have many mp3 files without a separator between the title and artist in the filename.
I need to insert "-" after the title (which is in capitals)

Example:
MY NEXT BROKEN HEART Brooks & Dunn.mp3
OUTBACK CLUB Lee Kernaghan.mp3
RIDING MY THUMB TO MEXICO Johnny Rodriguez.mp3

Need to be:
MY NEXT BROKEN HEART - Brooks & Dunn.mp3
OUTBACK CLUB - Lee Kernaghan.mp3
RIDING MY THUMB TO MEXICO - Johnny Rodriguez.mp3

Thanks in advance.

[Luuk]

With RegEx(1) having a checkmark for 'Inc.Ext.' the "Match" and "Replace" can be like...
^((?:[A-Z]+ )+)([A-Z][a-z].+)\.mp3$
\1- \2

If it doesnt match some artist-names, could simplify it like...
^((?:[A-Z]+ )+)(.+)\.mp3$
\1- \2