For example, I have on my app two options - `A` and `B`. I want to send my Push Notification to **users** who chose the `A`, **only**. How can I do it?

How can I separate my users and chose to whom to send my push notification, to the users who chose `A`, or to users who chose `B` option on settings of the app?

Can you please describe me this process or just provide me a plan. I'll do it for the first time, so it would be very useful for me