Otioni, That method will need the mobile license, for a mobile phone to ring within the group.
if you want option 1 to go to a mobile (not ring any where else first) you can either set option 1 to call a portable station that is forward to the mobile number or a group that is forward to the mobile, you don't need members in that group.
If you want some phones to ring first then go to a mobile you can setup the group with intercept to the PS that is forwarded to mobile
like Otoni said, you will need to allow fwd to co in class of service that phone or group is in.
you can use this if you have ISDN or analogue lines with CPC signalling or reverse polarity enabled or else the lines will not clear down when the call ends