Instead of displaying multiple notifications, you can create one notification that summarizes them all. For example, a messaging app might have a summary notification that says "3 new messages.” Upon expansion, it could show a snippet for each message.
To set Inbox Style, add the following payload fields :
Payload field key: inboxStyle
Value: If true, notificaiotns will be stacked.
Payload field key: nLocale
Value: summary text, default is new notifications.