Storing an XPath fragment in a variable

I'm using the following partial XPath expression...:

[name()='RED' or name() = 'GREEN' or name() = 'BLUE']

... in several locations in my stylesheet:

<xsl:for-each select="/*/*[1]/*[name()='RED' or name() = 'GREEN' or
name() = 'BLUE']">

<xsl:for-each select="*[name()='RED' or name() = 'GREEN' or name() =
'BLUE']">

Is it possible to store a fragment of an XPath expression in a
variable or is there another method of eliminating redundancy that I'm
not aware of?

Thanks in advance,
Jason