Crystal Reports If criteria met then distinct count field

Message

   Hi

I have a problem that I need some help on.

Example data is at detail level:

Date                  OrderNo        Order Type      Sales      Name
01/12/2010       A1234           Call In              £20         Peter
01/12/2010       A1235           Call Out           £25         Tim
01/12/2011       A2234           Call In              £30         Tim
01/12/2011       B2235           Call In              £30         Peter

My dilemma is that I need to provide a distinct count of the OrderNo field based on the criteria if date in range and if Order Type Call In or Call Out and then summarise by each Salesmans Name

Any help solving would be greatly appreciated

Kind Regards