Notification of cost commitment to project managers

Hello,

we would like to send an email notification to the appropriate project manager when a commitment is going to be charged to their project; i.e. a purchase req through iprocurement.

What is the most effecient method to accomplish this.  we are on 11.10.2, iprocurement, using AME approval workflow.  We do not want the project manager in the approval process - but, want to advise them.  it is too cumbersome to ask them to always run reports etc. to get to the specifics.

Any advise would be helpful.  thanks - Lisa walton