How? There is no option except in security settings, blocking access to all contacts by turning off sync contacts. There is no way to pick and choose contacts with this stupidly created app. The worst part is, those contacts I didn't want in my telegram feed, are contacts I need to keep but am avoiding. Nowv they got a notification about my telegram presence and thus I am very upset. F'n telegram thinks they know what we want. Idiots.
Because of this I'm looking at other similar social media, and not Facebook or Twitter. Google has a new one out. If that works for me I'm going to convince my group to move there, or wherever respects the users.