Is it possible to grab related entries that have been attached to a certain field?
If you want to limit your relationships to a particular field, use this syntax:

$criteria-&gt;relatedTo = array(
    'targetElement' =&gt; $element,
    'field' =&gt; $field
);


I believe 'field' will take:

1) A single or array of $field instances

2) A single or array of field IDs or field handles.