Select to array and visa-versa

I have a database table that will hold a list of tasks, each task will be assigned to one, or multiple authorized users to my app.
I have created a query in server connect that lists the users, and have used this to populate a multi-select.
To the right of the multi-select that is blank when the form loads and will contain the name of users that the task is assigned to.
What I want to happen is when the user creating the task and selects a user from the left multi-select, it gets move to the right multi-select and is removed from the left.
Then end result is that the user that it imputing the data can move task users from one of the selects to the other by clicking on the name. so if it’s on the right, it will move to the left, and if it’s on the left it will move to the right.
How would I accomplish this? Below is an image of what I envision.