to Purrs
First is that you cant train a cat, they train you |LOL
However I am having a problem visualizing the property, you say you live on the ground floor flat of a tenament and she keeps opening the tenament door.
I am probably being really stoooooopid but if you are on the ground floor, does this mean the entrance and exit to your flat is a different door to the door of the tenament?
If so why dont you keep her in a night?
Going back to what I first said, all cats are different and some like to chat and cats are not like dogs, you cant stop them. I have chatty birmans LOL
How old is she and if elderly and this noisyness is new, you should get her checked out by the vet, otherwise she is trying to get your attention because she has figured out that you have a door and wants to come in , maybe