how to rewrite and replicate accounting?

[Justin Church]

I want to take all accounting packets received and either rewrite 
received attributes or append new attributes using a custom dictionary 
and then replicate the rewritten packets to multiple radius servers. 
Freeradius documentation seems to indicate this should be doable, but I 
can't seem to find any specific examples.  Looks like I need some 
combination of the rlm_attr_rewrite, rlm_preprocess, and rlm_proxy 
modules?  Is this correct?  Thanks in advance.

-jc