Is it possible to use a parameter as the select element in a sort tag?

<xsl:sort order="{$sorder}" select="$searchTerm"/>

Im trying to get the order based on the $searchTerm

ie.

so if $searchTerm = books/authors then in the xsl it would
sort by books/authors.

<xsl:sort order="{$sorder}" select="$searchTerm"/>

is this possible?
I cant get it working, is there another way to do this?

thanks!