itunes grouping ipod

Does any body know how I can add more music to my iPod to iTunes kept me remove and add back again?
Well I iTunes My team and I have three set of bands is gospel, jazz and R & B and if I add more music to my jazz playing all dose Itunes suddenly wants to wants to do and start to sync my music anywhere so if anyone knows how I can do this without adding and removing iTunes please me help with this.Thank You Very Much!
assuming that these are not "smart" playlists that you created, you can select the songs want to add, right click … .. "Add to Playlist", select the playlist you want to add these songs to the
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