Random Date Assigned To A Member

Hi! I have an app where i need to associate each group member with a random date. For example if there are 12 members, I want to give each member a random month from the year: For example:: Bob: January, Alice: July, etc. I want this to stay in the data base until that’s years cycle is complete. So after a year, those dates will delete and new dates will be appointed to each member. I also wanna keep in mind that each month will be added in respective to something called “StartDate” this will be when i want the whole thing to start. so for example if bobs date is “Bob, June 31” I want Alice to be “Alice, June 31” But i want the actual assigning of each date to a random user.

Thank you!