In Views how to configure a contextual filter to exclude the node being viewed?
The problem I believe is the relationship. I assume the entity reference on each event points to the parent event, including that on the parent (recursive).

Get rid of the relationship. Set up two contextual filters, one on Content:Nid and the other on Content:field_parent.

On the configuration for the contextual filter on NID, set the default value to Content ID from URL, open up the 'More' settings, and select 'Exclude'.

For the contextual filter on field_parent, set the default value to PHP Code and use something like the following:

$node = menu_get_object();
return $node-&gt;field_parent['und'][0]['target_id'];


This will get the ID of the parent from the current node, and will require all nodes displayed to have the same parent. The exclusion of the current node from the list will work, and you will have a list of all other children related to the same parent.