vacation/on call schedule calander

Hello all,

 

Im looking for some help with creating a calendar that I can input employee's vacation weeks. I also need to be able to put names in for a weekend on call schedule, but i would like to use a function that will reference the name of the employee on call and flag it with a conditional format if their on call overlaps their vacation. Ive attached a test spreadsheet that i have worked on thus far.

 

Thanks in advance for any input.