I don't see numbers in your legend, I see text descriptions. So I'm not really sure what you're trying to achieve?
Yo'll need to upload a Tableau Packaged workbook though, I can't troubleshoot any further without an example to work off.
Hi Tricia, i had the exact same problem in a very similar type of visualization (using a parameter to filter by various sub-groups).
The only solution i could find was recode the variable in the data source to use actual subgroup names, rather than numeric values, although this of course can also be achieved inside Tableau with a calculated field, e.g.
IF [Subgroup] = 1 THEN "Subgroup 1"
ELSEIF [Subgroup] = 2 THEN "Subgroup 2"
I'm interested to hear from Tom W or someone else has figured out how to use aliases.