Android Question Firebase for selective users

Dear All,
Good days,
Regarding to example at:

https://www.b4x.com/android/forum/t...s-firebase-cloud-messaging-fcm.67716/#content

There are any way to send fire-notification for one or more form app. users.
example: at sender side, will select some users to send message, and other messages for others.
even I hope to make this selection come from database at sender side.

thanks on advance.
best regards