Keep GameObject destroyed on returning to the scene

Scenario: You are in Room A with enemies → You kill the enemies → You go to Room B ( Application.LoadLevel("Room B"); ) → You return to Room A ( Application.LoadLevel("Room A"); ) and keep the enemies dead

How would I go about doing this? Each time I return to the Room A, the enemies respawn.

Dependent on how large your levels are it might be better to have them in the same scene just in different locations and instead of reloading the level you can move the player to where they would start.

This would probably be better than reloading levels each time.