I have two test pages where the conversion pages are the same for both tests.
Should I just be able to do something like this on the conversion page to include both tests as a goal (notice the 2 '_trackPageview' on the same 'gwo' object):
var _gaq = _gaq || [];
_gaq.push(['gwo._setAccount', 'UA-123456789-2']);
_gaq.push(['gwo._setDomainName', '.mydomain.com']);
_gaq.push(['gwo._trackPageview', '/xxxxxxxx/goal']);
_gaq.push(['gwo._trackPageview', '/yyyyyyyy/goal']);