[xsl] Matching a bundle of elements

[Emma Burrows <Emma.Burrows@xxxxxxxxxxx>]

I am converting a large body of legacy XML documents to a DITA-based format
using Oxygen 12. One of the problems with the document I'm currently working
on is that about 15 different element names in the source will be turned into
<topic> elements. I'm finding that I'm having to repeat those 15 elements in
various templates in order to create the document maps, normalise cross
references, etc. This makes the code difficult to read and is also prone to
error if I accidentally miss off one of the elements in a given location.

Is there any way in XSLT 2.0 that I can define the source elements as a group
and then refer to that in templates, for-each loops and so on? Or are there
any extension functions out there that might help?

Thanks!