Where is the privacy code located?

[rufio]

(Sorry for making lots of silly modding question threads.)

I know that code for determining which sims get shooed out of the bathroom when someone is trying to take a shower is in the Enter Shower BHAV (and presumably the rules for shooing because of other activities are in similar places corresponding to the activity).  But where is the code that prevents sims from entering a door because someone on the other side is demanding privacy?  Specifically:
If someone is using a standard-issue bathroom, no one is allowed in unless they are both adults in some kind of romantic relationship.
If someone is using a communal bathroom (with only communal bathroom fixtures) anyone is allowed in, except:
-- if someone is *showering* in the communal bathroom, children are not allowed in, even if the person showering is also a child.

I want to make it so that children can use communal showers without preventing other children from entering the bathroom.  I've looked through any number of door- and routing-related BHAVs, and can't find anything that looks relevant.  Help?

[J. M. Pescado]

The privacy code tends to be all over the place, and varies widely by item. You'll have to dig in the individual item, possibly in the semiglobals.

[rufio]

So just change things until I somehow manage to achieve the desired effect?  Bleh.  Thanks anyway.