This could be interesting... The first thing that comes to mind is the plague event. It's always bugged me that the Yor are effected. If this were implemented the plague event could be taylored so only certain races are effected. Other events, such as a computer virus for the Yor, could be created to spread the love...so to speak.
Another example might be an event that stalls military production for a time. For some races it could be a worker strike, for others a raw material shortage... One could get really creative with these.