How to turn off the ringtone?

Hi,

I'm dealing with around 10 spams every single day. So, I just want iPhone only ring from the specific people. I already set up the ringtone for my family and friends, but can't turn off the default ringtone. It is really frustrating.

Do you have any good idea for this issue?

Please don't say, "Switch to the silent mode." Then I won't be able to get any phone call from my friends and family. I already tried the common methods. Plus, I don't use iTunes. I hate it.

I really don't understand why Apple does this. It's really simple though. Just add silent ringtone, Apple!!!