How to set the incoming call ring to 2 Extn (e.g. 1788 & 1800).

Hi All,

Need some help on Fortivoice, 

How to setting the one DDI (66281788) line to Ring at 2 Extn ( e.g. extn 1788 & 1800),

Also want to set the call ID follow the DDI (66281788) line on outside peoples Mobile phone display.

Thanks

Edward