How Can I Share Photos on my AppleTV from Multiple Disks?

My photos are located inside folders on two different disks: inside Pictures on my iMac's internal hard drive, and inside another Pictures folder on an external hard drive. One drive holds my Photos library and the other drive holds photos from Aperture and Lightroom. When i go to iTunes (12.3.1) on my iMac and select File -> Home Sharing -> Choose Photos to Share with AppleTV, I have to select the photos location in a drop-down menu. Even if I select "Other," I can only choose the Pictures folder on one hard drive or the other--not both. Is there any way to have AppleTV (4th generation) share selected photo folders from multiple hard drives?