When I'm designing my branch, I have some ideas again.
To give feedbacks of your reputation, we just need to do some small adjustment. Design some referrers, act by npcs who already exists.
1, Having sold a D-/C- slave to someone of a new district, add some texts, "A nice deal/slave, Jack, I'll introduce you to some of my friends. You have my word, I'm sure guys of camila house will welcome a talented slaver. Come to me whenever you are in need of renting a house here."
Then unlock B+ quests in their residence. If you don't have the right to live here, visit your customer again, (s)he takes you to the realtor_office as your referrer, in which case we just need to add a $customer_name[$npc_id] used in dialogs, after that you get the access to living in this district.
Then we have a feeling that, it's my slave who win it for me.
2, The gentleman's club, if no referrer, holds a higher demand to join.
3, The most improtant patricians, how can you be able to visit them without a referrer or some honor?
I guess we need at least a B+ customer as referrer.
4, If you have finished the cardinal's quest, give you access to all customers except kings.
"I heard of you, Jack, distinguished guest who can be audience with the cardinal. Come in please."