Identify letter combinations where order is not important?

From: D r . P r o z a c (prozac_at_gmx.net)
Date: 10/19/03 

Date: Sun, 19 Oct 2003 15:30:27 +0200

Hi,

I want to identify combinations of letters (a-z)... to make the combination
unique, but where the order of these letters is not important.

For example:
    'er' and 're' should have the same unique identity. 

-- 
Thanks in advance,
Peter.