set up Valgrind for multiple targets

I'd like to be able to use Valgrind on both x86 and x86-64 binaries running
on my x64-64 linux system.  I quite familiar with building and using
Valgrind on X86-64 binaries, we use Valgrind as the framework to build our
DynComp tool to do comparability analysis and type inference of C/C++
programs.  I would like to do the same for x86 binaries, but I am unsure of
the process to setup a secondary target.

I would be grateful for any suggestions.
Thank you
Mark Roberts