You can edit push notifications for specific Blrt conversations by: 

1. Selecting the Blrt conversation you want to enable others to add people to. 
2. Once the conversation is open Tap the '...' (triple dot) icon in the top right corner of the screen, this will open up the 'Conversation options' screen.
3. Go to the 'Mute push notifications' tab and toggle the option on or off.