If you make the parameter get its values from a dataset, it's pretty easy.

Right-click the parameter you want to show as a value list, go to Parameter Properties.

Select "Get values from query" (You'll need to create a dataset to populate this...)

It should include the Numeric value in one column, and then the associated text value. Something like:

SELECT GroupID, GoupName

FROM SomeTable

ORDER BY GroupName

Specify your "value" field to be the number you want to match on (filter your dataset with) - in this example, that would be "GroupID"

Specifiy the Label to be the text field that means something (in this case "GroupName", because the GroupID's don't really mean anything to people).

Then you should be off to the races.