Private pipes is a great feature available for users in the Business and Enterprise plans.
It enables you to create pipes that'll only be visible to your company admins and to the company members you invite into the pipe.
How to make a pipe private
Making a pipe private is a two-step process. First you'll access your pipe's settings by clicking on the gear icon on the upper right corner of the screen, then selecting the "Pipe settings" option:
After that, you'll scroll down the screen until you find the "Permissions" option, select the "Private pipe" option and save.
The second step is opening the sidebar again by clicking on the gear icon, then opening the start form settings.
Inside the start form settings, you'll scroll the screen all the way down and uncheck the box that says "Allow all team members to create cards on this pipe".
Hit save and, that's it! Your pipe is now private and will only be displayed to company admins and users you invite to join this pipe.