Within the X10 protocol it is possible to select several unit addresses which are on the same housecode and then send one or more commands that will affect all of the selected units at the same time. This is called “stacking” the addresses.
This allows you to do things like simultaneous control of a set of lights at the cost of a longer response time before the lights begin to change their state.
This command is specific to the X10 protocol and will do nothing to any other device or interface type.
send address for (name of Unit you wish to “stack”)
--brighten 3 separate kitchen lights at the same time together. send address for "kitchen Overhead" send address for "kitchen downlights" brighten "kitchen table" to 100
Only the last unit referenced will update in the database, so if you wish the database to remain in sync (which you do) you should also add something like:
brighten "kitchen overhead" to 100 with no transmit brighten "kitchen downlights" to 100 with no transmit
to make sure that the database values reflect reality.