Modding my Baktrian campaign to assimilate Makedonia

Hey all,

I need some technical advice on how to do something in my long-standing Baktrian campaign. I've scanned through the epic Makedonian AARs of MarcusAureliusAntoninus and want to try to do something similar to his really interesting process of dividing up his Makedonian empire and starting a civil war. Mine should be much easier, but I can't figure it out at the moment. A little background...

It's 150BC in my Baktrian campaign. I've pushed my empire westward to the eastern borders of Asia Minor, transferring my capital to Seleukia. I've chewed through the Saka, Pahlavan, and Hayasdan factions, and have raided the cities of the Saba to remove them as a regional threat. I am currently locked in war with the final remnants of the Seleucids, Koinon Hellenon, and most recently a very powerful Qartadastim faction east of the Nile Delta.

My ultimate goal with this campaign is to restore the Empire of Megas Alexandros. There is a tiny remnant of the once great Makedonian nation, isolated on the island region of Mytilene off the western coast of Asia Minor. I am confident that this remnant would be honored to join the new Baktrian Empire and help me restore what was once the greatest empire on earth. So I want them to join with me, as the nucleus of a "Western Baktria" that can initiate further westward movement into Greece and the Makedonian homelands. I think it sounds pretty reasonable as a game event -- and not too gamey...right?

All great in theory...but how do I accomplish this in the game itself?

I want to convert the region of Mytilene into a Baktrian province, and I want to convert the region's two remaining full-stack armies -- one with both Faction Leader and Faction Heir -- to Baktrian armies. I would like to do this with creative use of Forced Diplomacy and other tools, but I don't know if this is possible since I can't bribe the Faction Leader's stack and I can't ask the Makedonians to give me their last province. I suppose this can be done, but I can't figure it out. Can anyone give me some techical guidance on how to make this happen?

Hope this make sense...thanks in advance!