However, I have seen that document already and it doesn't look like I can fetch by multiple relations.
The only way I can see to do this, as underneath the objectrelations datatype uses XML in the data_text field to store the relations, is to do multiple fetches ( one per relation I want to match on ) and then build an array of node_ids that have objects which match all 3 requests.
Pretty inefficient.. Another way I can think is to create a new datatype which uses the object link table instead of XML.. but I wonder if there are any solutions out there which will already work with a simple fetch using attribute filters.
object relationlist already use the object link table, look at this extension for code (it uses the extended object attribute filter for relations filtering).
Relations filter ( comment by Kristof Coomans ): http://ez.no/developer/contribs/template_plugins/objectrelationfilter
