Just like this ? but this just can be control Music ?
this script can change,can only control 2 devices,not flexible。。
set output1 to 1 --change this to the actual 'line number' of your first output speaker
set output2 to 4 --change this to the actual 'line number' of your second output speaker selection
--the rest of the script will use these vales to toggle between the two
tell application "System Preferences"
reveal anchor "output" of pane id "com.apple.preference.sound"
end tell
tell application "System Events"
tell application process "System Preferences"
repeat until exists tab group 1 of window "Sound"
end repeat
tell tab group 1 of window "Sound"
if (selected of row output1 of table 1 of scroll area 1) then
set selected of row output2 of table 1 of scroll area 1 to true
else
set selected of row output1 of table 1 of scroll area 1 to true
end if
end tell
end tell
end tell
quit application "System Preferences"Preformatted text