First thing, you have a DIMMER not a SWITCH. You can't set different "zones" with the Maestro series, you have to jump up to the Spacer to get that. Have you already hooked up the rope light? Is it LED? If it is, then it's not compatable with the dimmers. You will have to get a switch for it.
Second, I know it's too late, but if you could have done a little more research and bumped up your budget a little, you could have gone with a URC remote and the URC/Lutron dimmers. URC remotes are alot more durable than Harmony. Their dimmers operate via RF directly from the remote and can control many seperate "zones". The dimmers look exactly like the Maestro you have but without the black IR window on the front of it.