I am also looking for this. (I'm using origami, btw)
The project has a ton of sources, with more included every day. (8852 at this moment...)
At any moment I'm working on a subset of them. I will frequently - several dozen times a day - switch to a different subset for a moment. Often go back-and-forth between several subsets at a time.
Most subsets have some common files.
I don't want to make each subset a different project (tried that for a while - very unpleasant).
I want to mark several tabs as 'MME' and others as 'SGW' and 'S1AP' - and stash 'PGW' while I work with MME and SGW. Stash MME; work on SGW and PGW. Then stash those and return to MME and S1AP.
You get the idea - hide the files I'm not interested in for the moment, with the ability to open them just as they were when I do want them.
Groups often have common files; different depending on the groups. And I don't want to open all the 'SGW' or 'S1AP' files; just a few of them.
I often have many (50 or more) tabs open -multiple tab rows and small tabs. Often a few with the same name.
Right now I just live with 4-5 tab rows - each group is a row of tabs. Wastes a lot of vertical space, but at least it's semi-organized...
I also tried multiple windows - that was worse! I kept bouncing between 4 or 5 windows, and often went to the wrong one. Very irritating.
(btw I work in web browsers the same way - many, many tabs open...)
It would be very nice to be able to assign a color for each group, too - visually distinguish them.