This one is now possible (I'm running Jekyll 3.7.2, I'm not sure which version it was implemented in).
Here's how to do it: in _config.yml you can define your collections as well as a folder for your collections. Let me take a look at an example on a client site that I am working on:
collections: events: output: true work: output: true jobs: output: true cases: output: true permalink: /work/:name collections_dir: pages
collections_dir: [your_folder_here] will tell Jekyll to look into this collection folder. My folder structure in development is as follows:
pages/ ... _events/ _work/ _jobs/ _cases/
And on the compiled site it looks like this:
... events/ jobs/ work/ (contains both "work" and "cases" collections)
One thing was also not set, but I found it useful, that you could display different collections in the same folder . In my case, I had a client site that had two types of working samples: client and general examples. We wanted to separate them for better service, but also show them in one folder. To do this, you can simply define a permalink for the collection. In our case, we put permalink for cases in the work folder ( permalink: /work/:name ).
Hope this helps!
It is also present in the Jekyll documentation
source share