Who the hell created a Greek-Serbian-Russian alliance?
Ever heard of the Nice or Lisbon Treaties?
Simply wouldn't happen, no matter how close Serbia and Greece are.
The facts of the matter is, if Serbia attacks Kosovo, the EU by Qualified Majority Vote would go to war with them. And that includes Greece.
I claim the Nordic EU battlegroup nations (Norway, Sweden, Finland, Ireland, Estonia).
Orders:
1. Requests air support from larger EU nations for the defence of Scandanavia.
2. Set up defensive cordons in the Finnish and northern Norweigan passes.
3. Use special forces to sabotage Russian forces in Murmansk, Karelia and St.Petersburg federal administration areas.