bulk edit of group of selected photos

suisekiart

Hi all, I need some help. I have searched all over, including in help, and haven't figured this out. I have a gallery with captions. I want to copy a sub-set of the photos to another gallery. The sub-set can be found by searching on a particular word (or phrase) that is in the captions. But I haven't figured out a way to do this without manually selecting each individually photo and either A) "collecting it" into the other gallery or adding a keyword (photo by photo) to allow me to set up a "smart" gallery. Is there a way to do either A or B without individually editing each desired photo? When I search on the identifying word in the caption I get no options that allow me to either do a bulk "add keyword" or a bulk "collect". I hope one of the experts here can give me some direction. Thanks!