Killing ships of an enemy power will get you a PowerPlay bounty by that power (that can be cleared at a IF), but it will not increase your notority. So if you are in a system controlled/exploited by the power to which you are pledged, all ships of enemy powers should be 'Enemy' and 'Wanted'. Similar but the other way around, disregarding of the current system, all ships of other powers will be tagged as 'Enemy' for you. Somebody else may confirm, I think* all ships of enemy powers toward the controlling/exlpoiting power of the current system are tagged as 'Wanted'. If you are pledged to ZH and are in a ZH system, you will not earn merits killing ships of enemy powers.