There is an arbitrary number of sequences, sometimes containing items with the same name:

(k, o, p, c, f)
(d, e, f, g)
(k, f, z, o)
(a, b, c, d)

I want to create a master sequence which contains every item once, preserving the original order.

Doesn't xsl:for-each-group over combined sequence solves the problem?
--
Vladimir Nesterovsky
http://www.nesterovsky-bros.com