Hi Emma,

On way to tackle this is to have a button on your form to Submit with code
behind.  In there, you can send an email through code.  You ca also store the
status of your form in a node so that the form knows which email to use.
It could be as simple as storing the step number in a hidden node: 1 through
10, and using a Case statement in your code to decide which email to use.

As an alternative, you could have have multiple submit buttons in your form
(each one sending an email to the appropriate user).  The buttons would
show/hide based on rules, so that only one button is active at one time.  
Step 1, button 1 is visible.  Once clicked, email is sent, button 2 is
visible, button 1 is hidden, etc.

Hope that it helps.

Regards,

Franck Dauché