Struggling to understand how to do run time tag changes accurately

I am using recast graph, but i am struggling to know the right way to setup implementation for doors that have different tags.

So i have a door prefab which i want to place down on the navmesh between two walls which have nav mesh cuts, this door needs to change the tags under the door to “Staff Only”.

I am not sure how to correctly place accurate tags that matches the door’s shape/position.

Here is a terrible drawing for example:

Where blue is general walkable tag, red is Staff Only tag.

I tried graph update component but this updates an entire triangle and is thus not accurate to the door shape. I need this to work at run time not just during editor baking too.

What is the correct approach here?