Can I use LinuxLive USB Creator to create a multi-boot live USB key?

No, you cannot use LinuxLive USB Creator to create a multi-boot Live USB key.

LinuxLive USB Creator is absolutely not designed to do this. I'm currently focusing on making one LinuxLive USB working at a time.

Maybe in the future I will add such a feature but do not wait for it.

Instead, please use the other software available which support multi-boot such as:

Please do not use LinuxLive USB Creator if you already have a Linux on your USB key!! You might destroy it.