Possible to create cities that can't be razed?

[Cjb64]

Hi, I made a scenario that begins with a number of cities already in place, and I want to make it so that only those cities can't be razed. Any new cities founded by the player or AI however would still be able to be razed. Does anyone know how to set this up or if there's a map file I can open with notepad like you could in civ4? It would be nice if there was a checkbox in worldbuilder under the cities tab that would give you this option. Thanks.