Yammer Integration to get notifications

Hi all,

I am trying to integrate Yammer with ServiceNow and trying to pull in notifications where a user has been mentioned/tagged.
Till now, I have been successful to authenticate with Yammer using AAD token (Ref: Yammer API with AAD tokens Postman Collection - Microsoft Community Hub) 
But, when pulling in data using Yammer REST API (Ref: https://learn.microsoft.com/en-us/rest/api/yammer/messagesjson), I'm getting data only for currently logged in user. 
Is there a way by which I can pull data for all users within a particular time frame or if I can use some other REST API for the same?

#Yammer_integration

#Yammer
#ServiceNow