Idea to controlling two faction(s) at the roughly same time....

[Hax]

TCV: I haven't seen you around for some time!

If I were you, I'd go into the EBBS script and look for the lines that control the turns as well as the events that control the season. At every change of the season (turns 4, 8, 12, 16, etc) add the line "console_command control seleucid". I think that should do the trick. Don't forget that the next turn (5, 9, 13, 17, etc) should have the line "console_command control pontus" to switch back to the Saka.

Enjoy!