Suggestion: please add support for iPhone contact groups
People have been asking for a separate SmartLine contacts list for over a year, and this obvious feature requirement still doesn't exist. So, I assume that's a hard one. Here is an easier way to improve the situation (at least for me) quickly.
Add support for the GROUPS that already exist (at least in iOS - I have no idea if Android has the same option). I already keep my SmartLine contacts in a separate group in my iOS/macOS contacts. All you need in the SmartLine app is to support those groups. Two options for you to consider:
1) Add a Group selection option to the SmartLine app contacts page - this would be similar to the iPhone's native Phone app.
2) In the SmartLine settings, let the user select a Group, and then in the SmartLine contacts page only show that specific group. This has the advantage of not requiring any change to the SmartLine contacts page user interface. It's just a simple new settings option.
Thanks for your prompt consideration. (I'm logged in so I'm sure you can figure out where to send my consulting fee.)