title: Subscribing to new mail event of multiple impersonated user through one ExchangeService object
body: <p>I am able to subscribe to push notifications by specifying impersonating users' credentials and then specifying impersonated user's email in <code>ExchangeService.ImpersonatedUserId</code> property.</p>
  
  <p>However want to know how can I handle new email events on multiple email ids that are impersonated by one email id, since there is no collection as such on <code>ExchangeService</code> to specify multiple Impersonation Ids. In fact I think we can handle only one email id by using single <code>ExchangeService</code> object. And to subscribe to multiple user mail events, even through impersonation, I have to create multiple instances of <code>ExchangeService</code>. And also multiple callback listeners too. This is what I want confirmation about:</p>
  
  <p><strong>Q.</strong> Do I need to create multiple instances of <code>ExchangeService</code> and callback listeners to handle new mail event on multiple user id with impersonation?</p>
  
  <p><strong>Q.</strong> Without impersonation?</p>
  
  <p><strong>Q.</strong> Also want to know given credentials of impersonating user, can I retrieve list of all users impersonated by that user.</p>