Is it possible to split a screen and work between two projects?
No you can’t open one project inside of another and load it into a split, if that is what you are asking. If all you want to do is load two project windows at once: yes you can do that.
To adjust two windows in a tidy way side by side - almost like split screen - I recommend SizeUp. Yes, one can adjust two windows side by side by some modest mouse artistry. That’s what I thought, too. But today SizeUp is one of my most indispensable tools.