Collections are Filters on your Library. You can even adjust the default Music Collection (File > Manage Collections) to have Genre is not Christmas.

No I have not. I will review that and see if can figure it out. Thank You!

Have you tried making a new collection in the media tree options?.
There are plenty of ways to set your criteria in there.

Can't find anything about this but that could easily be my issue not MM's. I have a medium sized collection (~40K songs) and would like to be able to break it into collections, not necessarily be genre but maybe sometimes (like separating my Christmas music out. Is the only way to do this by playlists?