How to generate workflow to send alarm to certain user group in case that workflow is stopped as failed status

Dear

I am newbie of Adobe campaign, so it might be very beginner level questions. 

I want to create new workflow to send alarm to certain operator group in case that workflow of that instance is stopped as failed status. 

I want to add 'A' node to judge whether there's failed count from previous node. 

In case, count is over 0 , then go to '1'

              count is 0 , then go to '2'

What activity should I add in 'A' with what setting in  it ??

Regards

SJ