Custom attribute for all entities of a specific class

Hi All

I am using a custom attribute (external=true) to separate my external and internal doors however find it quite frustrating to have to add this to every door I add to my system. Is there a way I could add this attribute to all door classes with a default value of say “false”? I have also noticed if I rename a entity my customization seems to be removed, is there any way I can prevent this?