Bootable USB with both Yosemite and El Capitan

[nyxynyx]

Is it possible to create a Bootable USB with both Yosemite and El Capitan?

In Unibeast, it appears that I can only choose between either of them, so I need a new USB drive for each OS X versions. How about combining both into a single 32GB USB drive?

 

[Going Bald]

Is it possible to create a Bootable USB with both Yosemite and El Capitan?

In Unibeast, it appears that I can only choose between either of them, so I need a new USB drive for each OS X versions. How about combining both into a single 32GB USB drive?

You want both on your build? Easiest way is to install Yosemite, clone Yosemite install to new drive/partition, boot to the clone, then download the El Capitan install app and run it same as on a "real" Mac to upgrade the clone to ElCap.