In crystal reports group by the record that is from "one" side of one-to-many relationship. Move record (field) that is from "many" side to group footer. Hide details section -> that does what you asked for, it shows first record from many table. Is there any criteria for that record (the biggest or the smallest... etc?)

I just did this using "xtreme" sample db that comes with crystal. Joined customer and orders field, inserted customer & orders field in details section, grouped on customer... and did the rest as above.

Cheers,

Alex