You can configure an action URL for turning the paging setting off on a function button.
Eg. on the phone web page function keys, select a function key and set its type to Action URL from the drop down, then in its number field enter:
http://127.0.0.1/dummy.htm?settings=save&a...cast_listen=off
and save it. When this key is pressed now, multicast will be turned off.
You can choose another key to set it back on by the action url:
http://127.0.0.1/dummy.htm?settings=save&a...icast_listen=on
and save it.