How to compare against multiple strings in xslt

For comparing an xml string value against multiple strings, I am doing the following.

<xsl:if test="/Lines/@name = 'John' or /Lines/@name = 'Steve' or /Lines/@name = 'Marc' " >

Can any one tell me, instead of using 'or' in the above case, how can I check whether a string is existing in an set of strings using xslt.

Thanks.