Well, I've been making good progress on this, through trial and error.

I'm not sure it's working completely, but I *have* gotten it to turn the kitchen on and off.

What I did was add a second receiver, which I called "kitchen". I changed the 'power' settings so that it didn't have an on/off remote button -- like it was "always on".

I changed the "input" characterization so that it had inputs corresponding to the second zone (video1, video2, video3, video4, cd, dvd, tape, tuner), and the IR commands for changing the input by using remote commands to get into "input switching mode" ('multiroom' 'multiroom' 'up' 'select') and to switch inputs ('up') and to end switching ('select', 'select').

I then set up two activities, CD from Kitchen (based on 'play CD', using the 'kitchen' reciever), and radio from Kitchen (based on 'listen to radio', using 'kitchen receiver').
For both of these activities, I added an extra command, when the activity starts ('multiroom'), and when the activity ends ('multiroom', 'select', 'down', 'select').

You don't get "macros" except for sequences when activities start and stop.

One of the puzzles had to do with the difference in behavior of the device in response to the 'multiroom' remote command. If the device is on, or multiroom is already on, the 'multiroom' remote key selects the 'multiroom on/off' menu. However, if both the main reciever and the multiroom control is off, the 'multiroom' command will turn on the second zone.

SO: if the kitchen was last listening to the CDs, and I select the 'kitchen radio' activity, the act of switching the kitchen input will also turn on the multiroom. However, if the kitchen was last listening to the CD and I select 'kitchen CD', well, the input switch doesn't turn it on, thus the 'multiroom' command when the activity begins.

Well, that's the theory so far.