because the sort order is kind of hard coded when you create a group, one solution would be to create two formulas
and a Parameter on your Report
two formulas will look something like this:
@Sort1:
if {@Param} = 1 then
{MyTable.FieldX}
else
''
@Sort2:
if {@Param} = 2 then
{MyTable.FieldX}
else
''
create two groups one for each formula with a different sorting, suppress both header and footer on the groups
then pass a value from your VB interface to the @Param 1 or 2 depending on your criteria and Crystal will do the rest
Mo