You need to go to the courtyard are of the school (where you first ran into Kitty) there should be an option to "Visit the Brotherhood" or something along those lines.
I've the same as ryai, after having seen the scene they mentioned, the option you describe does not appear in the courtyard (University Square, assumedly), or any other location I checked at various times for that matter.
Version 0.984h_1, have not checked the Quarantine version. though I've tested all dialogue options in that scene, and checked with travel mode on and off, no new location.
Unless there are other requirements, I assume it's just a flag not being set, and I'd check the code myself, but apparently I can't open the archive in the way I normally do, and I otherwise only have an image unpacker on hand... So, If someone can point me towards a functional method to browse and edit or decompile the code, I'll take a look.