Sorting entries in a Filter

hi All,

I am grouping ranges of Ages together..like

if age between 0 and 10 - then 0-10 as age_group,

if age between 11 and 20 - then 11-20 as age_group.

When I use "age_group" as a filter the values arent ordered. I would like 0-10, to appear first in the list, then 11-20 and so forth.

How can I do this?

I'm thinking I could potentially add an extra field in my query with a numberic value, like 1 or 2 for the 2 lines above, and then sort by that value - how would I implement that?

Thanks