Here is the scenario:
The house has a full RadioRa system with the RS232 interface, XP8, and T2CZ's.
I am trying to make the bath fan turn off 5 minutes after the light turns off.
The bathroom has a Dimmer for the lights and a RadioRa switch for the fan.

Any help with how I do this would be greatly appreciated.

Relay off the above RA-SCI interface attached to a contact closure on the xp8 attached to macro with a 5 minute timed off comand. I think this will work but I have not actualy  used that particular RA interface before

Since this is using two way drivers, isn't there a way to see the change from the dimmer and then trigger the macro without using another piece.

I think I figured it out.

I created a driver event that runs a macro when the zone the light is on goes to off. The macro it runs is just running another macro in 5 minutes that turns the zone of the fan off.

I won't get this tested until the remainder of the lighting system is installed on the 28th but I think this should work.

You could be right as you can check zone status, however this is what the radio Ra driver info says

Master Controls in the RadioRA system can be used to trigger macros on the XP-8, even if no Room or Scene programming is assigned to them, by assigning a system macro to the appropriate Driver Event. Note that the RadioRA Master Controls will only send a button press notification for un-programmed buttons if an LED Control command has been executed at least once. Therefore, it is recommended that you create a "configuration" macro that sends an LED Control command to each un-programmed Master Control button you wish to use. This macro only needs to be used once to enable un-programmed buttons to send Button Press events. Refer to the RadioRA RS-232 Programming Guide section Controlling Non-RadioRA Equipment Using RadioRA Master Controls on page 13 for more details. This driver does not currently handle the "Cordless Waking Up" and "Cordless Going To Sleep" events described there, so it is recommended that LED control events are sent only to permanently-powered Master Controls at this time. A future driver update will remove this limitation.

Is it too late for you to get a Lutron Occupancy Sensor in there? The occ sensor will close a relay that would be sensed by the XP-8.

Probably not possible to get Occupancy Sensor. I am hoping the other solution will work. Has anyone tried this?