1. One way this could be solved is if the UN were to take away Russia's right's of being part of the UN and punish them to a point were they would have to give in to the force they are trying to beat.
2. Another way is that we could convince Russia to give up these act's and return to peace but this is the most unreasonable ways because if they were taking over a country they wouldn't get convinced easily to stop overcoming a country.