Round robin w/o closing backend connections?

[CJ Ess]

So lets say that I don't want HAProxy to close the connections to my
backend servers - they can stay active and be available for keepalives -
but I do want every request from the frontend to go to a different backend
via round robin. The idea being that it keeps one frontend connection from
monopolizing a single backend while not forcing me to close the backend
connection after every request. Is there a way I can do that with any
version of HAProxy?