ATR Authorisation - Ability to add notifiers at each stage in the authorisation chain

As a user, I would like the ability to add in notifiers into certain chains within my authorisation changes.

For Example my Auth chain follows as such: Manager raise > Line Manager > Head of Department > Chief Executive

However I want my Finance Director to be notified when the Head of Department has authorised the role.

User Story - To avoid a bottle neck situation where the FD has to approve each ATR, it want him to be able to notify on each of the ATR's authorised by HOD's to ensure they are within Finance Budget.