[Boost-build] Inserting an extra stage into the BoostBook toolchain?

Subject: [Boost-build] Inserting an extra stage into the BoostBook toolchain?
From: John Maddock (john_at_[hidden])
Date: 2008-11-15 07:35:59

OK, I have a very primitive automatic indexer, that accepts Docbook XML as 
input along with a concordance/script file and outputs another Docbook XML 
file with index entries inserted.  It would speed up development a great 
deal if I could insert this tool into the regular quickbook/boostbook build 
process, anyone have any pointers on how to achieve this?  And yes, I've 
looked at the extender manual, but can't see at present how to modify an 
existing tool chain...

Many thanks, John.