If you mean you want the six values to each be their own group, with the others in a separate group, then create a formula:
if not({table.value} in ["value1","value2","value3","value4","value5","value6"]) then "Others" else {table.value}
Group on this formula. This is the equivalent of grouping on {table.value}, choosing "specified order", selecting the six values to order, and then choosing the "Others" tab and selecting "display all others in their own group."
-LB