There are several methods to do this. For your needs you might try the following, which assumes that you have one group with multiple instances. First create three formulas:
//{@reset} to be placed in the group header and suppressed:
whileprintingrecords;
stringvar x := "";
//{@accum} to be placed in the detail section and suppressed:
whileprintingrecords;
stringvar x;
if instr(x,{table.field}) = 0 then
x := x + {table.field} + chr(13);
//where {table.field} is the field you want to display under
//each group name and assuming you only want unique values displayed
//{@display} to be placed in Group Footer #1b:
whileprintingrecords;
stringvar x;
Right click on {@display}->format field->common->check "Can grow". Drag your group name into GH#1a, and insert a GH#1c to allow for spacing between sections. Suppress the details section.
Next go to the section expert->details->check "Format with Multiple Columns"->layout tab->set a width and gap->check "Across then Down" (this will only affect the display of the group names)->check "Format Groups with multiple columns".
This will give you a display of group "headers" (in the footer section) with a list under each. If you only want to display one "row" of groups per page, then stretch GF#1c until the next group is forced onto the next page.
-LB