Is this function possible?

Would it be possible to implement a special search qualifier that causes your search to return images which contain only the characters you searched for and no others?
 
For example: if I am trying to find a specific picture which I know contains only Twilight and Rainbow Dash, searching for ts, rd returns tons of images with others from the mane 6, or other secondary characters like Scootaloo or Celestia, so you have to search instead for something like ts, rd, -(fs OR pp OR ry OR aj OR sl OR tia OR etc...) adding more and more characters until you’re left with search results which are mostly just Twi and Dash (this particular example works pretty well, but I’ve had others that took many more tags to yield usable results).
 
I’m thinking since you already have tags in categories, we could have something like ts, rd, category:character_exclusive (or some other syntax I dunno) which would exclude images containing any character tags which are not explicitly included in the search.

Stops at three characters, but isn’t that what the solo, duo and trio tags are about?
 
So, twilight sparkle,rainbow dash,duo for your first example?

@Roseluck  
Well, duo has in its description that it’s for non-shipping images. not anymore
Also, it depends on people using these tags reliably, which is less probable than the character tags being present.
 
Alas, I do not know of such a function currently implemented. It’d be useful for me too: I have excessively-sized blocks of mutually “or”d names in my filter, just to provide the functionality of “don’t show [x group of tags] unless [any canon character] is also tagged”

@Roseluck  
Yeah, like the other guy said, duo and trio would be great if people actually used them reliably, but they’re so frequently forgotten that including them often hinders your search more than it helps.

There’s no way to do this that I know of. I’d probably get good use out of this if it were a thing, though I’m not sure if it’s possible to implement this as a new search feature.

@Litrojia  
I didn’t think there was any way to do this now, I guess I should have clarified I meant would it be possible to implement this sort of function. You say you’re not sure, but I think it’s clear it would be very useful to a lot of people, so think y’all could look into it more in-depth at some point?

@Maonyman  
There’s a feature request thread for that.

@Background Pony #572B  
Ah right, I forgot about that. Thanks

Possible, but I don’t think it’s ever happening.
Yes, we could have a syntax that says “exclude all tags that are in this tag category except for these specified”, but it would be a lot of complexity to make it work, for very little benefit.

@Background Pony #572B
It’s been changed since this post - “duo” and “trio” are no longer excluded from shipping.

@Princess Luna
I recently posted a feature request for a tag-count-by-category search parameter, which would be another way to achieve the same kind of exclusion.