Thanks for the reply, Wizard. But I wasn't clear.
FF (and Chrome, and Opera and Vivalidi, etc.) have the facility to open multiple tabs with one click on a bookmark folder. That's what I hoped to find. I have a set of 15 comic strips that I like to view every morning, and it's really, really convenient to open all 15 with one click
Now that I've gotten F26 taylored to my specifications, I'm gonna play a bit with Qupzilla to see if maybe there's something in the new-fangled speed-dial new-tab page that lets me open multiple sites at once.