Need help in managing in AWS workspace running mode

Dear Amazonian, I had setup Amazon workspace POC in past & i was able to achieve our requirements. However i will setup another POC this weekend on AWS workspace - what i need to know is : Is it possible to auto stop workspace (ubuntu desktop) of our student after its 3hours of usage in a singel day ? as part of cost consideration - we dont want our students to use the desktop for entire day. I would be grateful if you let me know what options i have to achieve this.