Assigning a date to a value

I'm working on a gantt chart that is tracking teams progress on a project using agile development. 

Business Case / Background:

When the teams provide updates to when a task is going to be completed, they reference the name of the sprint we're in. So for example if "Task ABC" will be completed in Sprint 1A that means its end date will be 12/21/2018. I'd like to be able to have the sheet understand that the Sprint Name coincides with a specific end date. 

Issue:

I believe that I'm unable to have an End Date cell (if dependencies are turned on) be updated by a formula. 

If thats the case, I'm just going to use my calculated date field & manually update the official End Date using it. 

SO- how do I create a formula that says "If Sprint Name = 1A, then this field should say 12/21/2018"?

Thank you SO much in advance!