[xsl] Why can a template rule match on a child of multiple elements but cannot match on multiple children of an element?

["Roger L Costello costello@xxxxxxxxx" <xsl-list-service@xxxxxxxxxxxxxxxxxxxxxx>]

Hi Folks,

Why can I have a template rule like this:

<xsl:template
match="(sidRunwayTransition|sidCommonRoute|sidEnrouteTransition)/supplemental
Data">

But I cannot have a template rule like this:

<xsl:template
match="sid/(sidRunwayTransition|sidCommonRoute|sidEnrouteTransition)">

/Roger