threads?

I just read the manual for o:XML and it looks cool.  I like the way that
input and output to functions, etc. is all XML, and I like how you can use
X-Path anywhere.  Basically, o:XML is the scripting language equivalent of
XSLT.

However, although you can expand the language by defining your own
procedures (ie, defining your own tags), I can't figure out anyway to fire
off multiple threads and then wait for them to finish.  Any ideas?

Bill