A siege map. Lots of enemy melees make the outer ward a delicate battle ground.
It's necessary to use a large number of shields which may be an unfamiliar experience for some players: how your own shooters can stand longer and wipe out opponents as long as those shields remain intact.
Group all the shields by Ctrl + number, and group the archers in one or two groups by Ctrl + other number(s). Proceed carefully, anyway.