Yes its very much possible to make a Multi Boot USB, meaning you can have two Operating Systems on one USB either it can be the LIVE OS version or a complete ISO to fully install the operating system.
There are many great programs which will handle most of the stuff, i'll name a few so you may get started
- WinSetupFrom USB - Allows you to install multiple OS on a single USB , details can be read on their website. The program and process is self explanatory so it wont be any issues for you to set you one.
- YUMI - Your Universal Multiboot Installer or YUMI is a very robust and versatile program which gives you alot of flexibility and get the task done, again you can head over to their website and start your process. YUMI is bit faster then the above mentioned program but at times faster write speeds result in redundancy errors
Just download the program which ever you like and the process is simple but if still you get stuck somewhere you may ask a new question so we get you sorted out