Cannot Search for Photo Titles in My Passport

I just bought a My Passport portable external drive for Mac. I partitioned it so that one part is for me to move some of my “Photos” libraries from my MacBook Pro onto the partition. When I enter the partition and do a search for photos using titles, I get no results. So I can’t find any of the photos inside the libraries that I’ve moved onto the drive unless I open a particular library in the external drive and enter a title name in the search box for that library only. Is there a way to get the Passport Drive to recognize the titles of my photos for all the libraries I’m storing on the drive? Thanks for guidance.