Yes, this is possible in XSLT 2.0 (which, from the as="xs:integer" in your example, I assume youre using). The following transform will produce your expected output from your example input: <xsl...
The ancestor::Locus[1] is because we need to extract the Locus Id at a point where the current context is its first Allele. If you want to avoid adding rowspan="1" for single-allele loci, youll have to use a...
