Actually, I think a few intermediate scenarios are in order, as things heat up and get out of control in Balszakistan.
First, the Balszaki rebels (the Balszaki Freedom Front, or BFF), are pissed (not to mention a bit embarrassed) about the US's successful hostage rescue. So I think a BFF attack on the US Consulate in Balszakistan is in order (think about the movie Rules of Engagement...). That will lead to broader US involvement, one way or the other.
Then, I think there needs to be a border incident between Balszaki border guards and Russian Interior Ministry troops, which will give the Russians an excuse to intervene.
Then, perhaps an attack by the People's Balszaki Resistance (PBR) on Russian troops will introduce another faction. At that point, we'll have the US, the Balszaki Armed Forces, and the PBR aligned against the Russians, the BFF, and local armed gangs/thugs. That oughta do it...
Then I think the afore-mentioned fight for the bridge can be safely conducted...and we'll go from there...