Sending Appointment to Multiple Users of CRM and Non-CRM Users from CRM 2011

Hi ,

Let's say I have a Custom entity called A which is associated to (1:N Referential Type) other two custom entitiesB,C.

On B entity I got Participants of CRM Users(have CRM Accounts)

On C entity I got External Participants who are not CRM Users(Not having CRM account manually entering email).

I want to retrieve all the Participants(CRM & Non CRM users) emails and set to the "Required" field of anAppointment .

Also I want my appointment to be in "Save" state, don't want to send before veryfying.

How can I achieve that?

Please Help...