Let's say I have a "Blog Post" collection, with a reference (or multi-reference) field pointing to a "Tags" collection.
On the blog post template, I won't be able to display ONLY "Tags" that are related to this post.
It would be great to be able to filter them.
If I understand you correctly, you're trying to show only the list of multi-references on a collection template page. Ex: You have a collection of blog posts and each blog post references many tags. If you want to have a list of tags displayed on your blog post page, you can drop a new dynamic list and in the collections dropdown choose Tags collection under the Multi-reference section. (See screenshot). Our apologies for this being hard to discover. Can you confirm that this is what you're looking for?