I don't seem to find the 100% safe way to link an address with a notification.
I did use a similar code to what is described in this blog and it works, but it seems a bit dangerous to directly use IQS0_MODIFY_NOTIFICATION (I used IQS4_MODIFY_NOTIFICATION and it also works). : https://answers.sap.com/questions/364951/generating-adrnr-for-notificationequipmentfunction.html
However, I don't seem to find a BAPI or a good alternative from SAP to solve this issue in a safe and future proof way. Maybe I'm missing something, because seems like it should do a quite common action.