Targeted publication is mostly about inbox relays because you'd be "tagging" your selected profiles in their inbox with the event you want to share exclusively with them. Your personal relay is already part of the event, so their client knows where to look. 

Next you need good UI that makes it clear that it's a private publication.
I use this kind of headers: 
https://cdn.satellite.earth/7bcfe1478007d70033b5e22667be930cb91608923ddf3fa9f5f9270e6c8899b9.png

Which matches nicely with the targeted publication you can do with Community relays: 
https://cdn.satellite.earth/da6911b627e2d19096bc57d3259b06dfa54f1401a6688c4beac3db5cc5d6c62d.png