This has been at the top of our list ever since we added the ability to make resources visible to clients! We realized (very quickly) that it was a pain to add a resource one client at a time. Especially when we wanted to add a recipe collection to a whole group or even a workbook for a particular challenge.
We solved that issue!
Now, from the Client Index page, you can select multiple clients and choose Add Resource from the bulk action menu.
On the next page, just add a title, choose the pdf and check the Publish box if you'd like to make this visible for your clients. It's a simple, quick way to share pdf's with multiple clients with a few clicks.