Person/Group already notified in the email notification

Hello,

Is there anyone who has implemented below functionality or any ideas on implementing this?

Say there is a coverage with escalation in the order of A,B,C with delay of 5 min. between each.

Escalation      Person/Group

0                         A

5                         B

5                         C

Now, when a notification is sent to A, we show in the email notification that A is the first person being notified.

No action taken by A.

When notification gets escalated to B, in the email we show that A has been notified.

No action taken by B.

When notification gets escalated to C, in the email we show that A,B have been notified.

Thanks

Rohit