Picasa has/had folders and albums so my head is all screwed up with this terminology.
I have my photos (45,000) stored into folders (albums?) based on area of interest (like MyFamily, Wife'sFamily, etc.)

I am trying to find an easy way to create Picasa type albums like "My_Trip_to_Itlaly_in_2013" which would be a subset of one of those folders.
So I could highlight and easily access my photos from that trip.

Thanks, Any help would be appreciated