Display all nodes with identical field value to current node BACKGROUND:
Site is using content types which are auto-created through Rules, called CT-A and CT-B. CT-B represents a full URL, and CT-A represents that URL domain. CT-A is always created via Rules only once, the first time a content type CT-B is created. Both content types share a field (field_domain) specifying the domain. The original content is user entered, so it isn't possible to predict the value of field_domain in advance.

ISSUE:
I need to display a simple 'related content' type view in CT-A, showing all nodes of type CT-B which match the value for field_domain. The value for field_domain cannot be pre-defined, and needs to be provided program / systematically, either by being taken from the field in the node, or as a token (same difference).

APPROACHES:
I am assuming the answer is in Views. Specifying a value for field_domain doesn't work, because the value changes based on user entry. I've tried Global: Field Comparison, but it doesn't seem to be possible to compare both the current node's field_domain and that same field in the nodes displayed in Views. I have tried using Views Panes to pass the argument for the current node's field_domain into the pane display, but it also didn't return results. I have seen various Contextual Filter PHP solutions, but they also don't seem to work (the most promising one is https://www.drupal.org/node/1006484#comment-4990312 , but this returns the following error: https://www.drupal.org/node/829250). 

Taxonomy hasn't worked, because of the auto-create nature. It doesn't seem to be possible to create unique TermID by passing values in Rules - the Term name will be the same, but the TermID is different, and Views judges the Term based on its ID. It isn't possible to auto-create a Term Vocabulary in Rules due to a bug with assigning the machine name.

Entity Reference also has problems with the auto-create nature. I haven't figured out a way in Rules to reference the two types according to field_domain value, and not sure if there is one.

Search API Tried this approach (compare the search index) suggested in the link below, but again it doesn't work unless you have a predefined value for field_domain, as it requires setting the value manually.

The most obvious approach seems to be "Views filter display all nodes with same field value. But despite being obvious, this doesn't seem to be easily possible. Perhaps there is a non-Views way which I haven't considered?

Related questions to this (all seem to be unsolved):

[apologies, I'm limited by reputation...but there are at least 4 open questions in related questions to the right which are still unsolved]

Throwing it open...seems like a few people have run up against this problem. Any new ideas out there?
The way I've always handled this is to build the view in question using the "field value to match" as a Contextual Filter. For the Contextual Filter's settings, choose "Provide default value", for the type choose "PHP Code", and for the "PHP contextual filter code", load the current node and grab it's field value,

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