Select preceding or following node

[admin]

How do I move through a node set? For example, I have 20 nodes named image. These are divided into 2 groups, by 2 distinct values set in the attribute "group" ie

either

<image group="1" />

or

<image group="2" />

When i select a node in group 1, how can I select either the preceding or following node in group 1 in the xml file.

I am trying to display each image individually, but have links to the preceding or following nodes. In short a kind of image gallery.

I have tried to use the axes commands precedent-sibling and following-sibling, but these select all preceding or following nodes.

thanks in advance for any help

wastlinger