Filter data tiddlers by value of an index

[David Allen]

Here's what I'm trying to do:

I have data tiddlers with the following information:

 - Name

 - Rank

 - Position

 - Begin Date

 - End Date

I'm trying to filter a set of such data tiddlers based on the value of a particular index.  Problem is, I'm not sure how to do this in a filter expression.

Does anyone know how to do this?