How to Group the names in crystal reports?

Question

Hi to all,

I have one table Partytypes,
in that partytypes are
1)seller
2)buyer

under seller i have two records
under buyer i have three records


My requirement is,in report i have to show 
under seller section i have to show  seller records only
ex:seller
1)--------------------------
2)----------------------------

same way to buyer also

how ?help me

thanks inadvance