automatic notications

dear,
I would like to notificated someone (idUser, or idContact, or someelse) with information or Alert format inside the projeQtor Software (not with email) for a new project expense, for exemple:

1- Transmitter create a new project expense
2- when he change the next workflow step (submitted for exemple), I would like to have a internal message for maybe IdContact or financial officer
3- then, the financial officer could check and change the next workflow step to valided or rejected, and a new message can inform the transmitter to this new status with an other message or notification...

is it possible? 
I try to to this with "definition of notification" module, but it is only pilot by a date, not by a status...

could you help me ?
 

ok, it could be a good way, juste to decrease the email number an, it's just to inform somone to do an simple action (like change status)