Can a post be part of two collections?

I have the following setup for two collections:

    permalink: /blog/{slug}/
    template: index
    filter: tag:blog
    data: tag.blog

  /release-notes/:
    permalink: /release-notes/{slug}/
    template: index
    filter: tag:release-notes
    data: tag.release-notes

I would like my release-notes to be shown in both, the /blog/ page as well as the /release-notes/ page.
However, it seems that when I tag my release notes with both, blog + release-notes, it will only ever appear in one or the other.
Is there a way to change that?

  /blog/:
    permalink: /blog/{slug}/
    template: index
    filter: tag:blog+tag:lol
    data: tag.blog

  /release-notes/:
    permalink: /release-notes/{slug}/
    template: index
    filter: tag:blog+tag:release-notes
    data: tag.release-notes

It seems like you’re looking for channels :slight_smile:

Ghost Themes - Dynamic URLs & Routing.

Posts can only be assigned to one collection

Oh! Well I think that was it but now all posts in my channels send me to the 404 page?!
Am I doing something wrong here? This is my new Setup:

routes:
  /: landing
  /docs/: custom-post-docs
  
  /blog/:
    controller: channel
    filter: tag:blog

  /release-notes/:
    controller: channel
    filter: tag:release-notes

I am still defining taxonomies and collections below. Is that a problem?

It seems like you want the primary URL to be /blog/a, but you also want to mirror the release notes to /release-notes/a. For that case, the blog route should not be a channel.

Channels do not provide posts with a home which is probably why you are getting the 404

Right. I got it now! Thanks!
Is this not explained in the docs or did I miss that?

Collections and channels take a little bit of time to get used to :slight_smile: There is this section in the docs though

Unlike collections, channels have no influence over a post’s URL or location within the site, so posts can belong to any number of channels.

Ah yeah there it is. Thanks for the help again.