There's a way to do it indirectly, but at a great cost. We did this a long time ago so the details will be a bit fuzzy, but I think we made a couple custom fonts that were green/red squares and changed the hud element that draws people on the scoreboard to use it in a new position.
You lose the ability to see peoples names because, at least back then, you can't duplicate elements, only replace them. So you're sacrificing seeing the names of people in the server on the scoreboard in order to see how many people are dead/alive outside of it.
I lost the screenshots I had of the real thing, but here is a paint edit that shows exactly what it
looked like. Assume here that the other team has 4 dead and yours has 2. Of course we stopped using it because it's too much of a hassle, it's easier to just keep track by looking at the death counter and having a good understanding of the respawn times.