lol, not sneaky, it's just what I had to do. I was bummed, because the one region I had there, I got from Ptolemy, and at the time I though Parthia was my Ally (which would've been good to satisfy the requirement), but after I took it, they were no longer my Ally and they were pissed at me.
I probably could've won a long drawn out battle with them (even though they were way more powerful, I'm sure if I hit their two army groups with 3 army groups and manually fought a lot of battles, it could be done (but probably would've taken another 100 turns). So not sneaky, but the 'lazy' way out. I guess I'm also lucky his armies were elsewhere on the map, and nothing came at me in the few turns it took me to take the other regions.