[xmonad] Screen independent workspaces

Is there a way to have workspaces on a per-screen basis? I have 3 displays and on each display I'd like 5 workspaces. Right now my 10 workspaces are shared across all screens, and I'm pretty sure this is the default behaviour. (I'm fairly new to XMonad.) I'm probably going against the grain of XMonad users, but this approach fits me better.