(hinterland_ problem) indestructible buildings.

Hello, I want to add Templar and Hospitaller guilds to Jerusalem and Acre, and so I edit the descr_strat, make Acre to a Fortress and add a minor hospitaller chapter house there, then I go ahead and add a minor templar chapter house in. So I start up a campaign and check that the buildings are there, great! Now I will surely have the orders waiting for me once I reach Acre and Jerusalem.

Once I take the settlements I find that the Templars guild in Jerusalem has been destroyed (probably by those damn Egyptians). So now I wanted to mod it so that the buildings are indestructible. I am told to add a hinterland_prefix, unfortunately I have no idea where to add it.

So that is my question: 1. Should I change the guild_templars_chapter_house to hinterland_guild_templars_chapter_house? 2. What file(s) should I edit? 3. What entries in those files should I edit?

Yes, if you want the building to be indestructible you have to do that.
As for the files, do a windows search for files containing the building name in your data folder.

Yea? Just to the guild_templars_chapter_house or also to the templars_minor_ch etc? Oh and I have to add a hinterland_ infront of every guild_templars_chapter_house I can find, or are there some exceptions?

It should suffice adding it to the building tree, no need to assign it to each level.
And there shouldn't be any exceptions, why don't you just run the game and check the error log, I guess it'd show you if you made a mistake