how to use the three argument variant of the button command to link three buttons.

[Terracotta-62]

Examples Playback Events by BT ,by time ,Playback Stop.

Thanks!

[myTonino]

Which "three argument variant of the button command" do you refer here? Custom event buttons can have a state but it is binary (see Buttons – Appearance, State, and Action).

You could define a sequence of 3 buttons which use a technic similar to example 2 of the post linked above to ensure that only one of the 3 buttons is active.