Multiple ID issue, can you help?

I have two appleIDs (near as I can tell, perhaps more with iCloud, sigh).

One is my @mac.com ID, from way back, and this is the one I use for my Apple email account. I use Mail.app on my MAC at home, and I use the Mail app on both my iPhone and my iPad. I also use this "ID"/email address to sync my contacts, notes, and calendars across those three devices.

Now, I have just upgraded to Maverick (10.9) and I want to share movies (using iMovie) to my AppleTV. Trouble seems to arise here because I have used a separate Apple ID (my iTunes ID from way back) on my AppleTV so that I can see/hear all the music that I have purchased thru iTunes over the years.

A long time ago, when I got these two IDs, it wasn't clear that they were related in any fashion.

I have read that a computer can only handle/manage one iCloud ID at a time. So, as I see it, I can EITHER log my computer into iCloud using my @mac.com ID - then sync my Mail/Calendar/Notes/Contacts, OR I can log my computer into iCloud using my iTunes Apple ID and be able to share photos/movies/music, etc with my AppleTV.

It's one OR the other.

Do I have that correct?

Is there any way for me to set this up so that I can use my MAC computer to sync my emails using my @mac.com address/ID AND share photos/movies with my AppleTV using my (separate) iTunes ID?

It seems to me this has only become a problem today when I upgraded to Maverick (10.9) as prior to this it seemed I could somehow use iTunes to do the music/photo sharing, and the rest of the MAC for the mail/notes/cal sharing to my other devices.

thanks for your reply.

m