[xsl] Is there an OR for XSL IF?

[GWmbox <gwmbox@xxxxxxxxx>]

I have had a read through the W3C stuff for IF elements but I cannot 
find anything conclusive about an OR for the IF elements.

Is there in fact an option for OR, is it the | to do this. Can I have 
something like

<xsl:if test="myfield/field_is_available/data = 'Yes'" | 
test="myfield/seconsfield_is_available/data = 'Yes'">

Or do I need to use something else.

Thanks for your help

GW