Allow searches filtering on object relations

In a specific website object-relations are used extensively.
As of 5.2, there is no way to use a field filter criterion to retrieve objects which related to other, specific objects.
This was added to eZPublish in release 2013.11

We need to either:

• have that criterion backported to 5.2
• or have the kernel allow loading custom criterion via DIC (public issue already exists: https://jira.ez.no/browse/EZP-20800 ), so that we can add such a criterion in a bundle

Can you provide one of these two solutions?

Thanks in advance.