The easiest way to do this is to add a silence instrument to the playlist of a multi instrument, and add a random modulator to the silence instrument’s duration so that the duration of the silence is randomized within a range each time the silence begins.
Then, all you’d need to do is set the multi instrument’s playlist selection mode to one of the sequential modes and set it to loop infinitely.
The disadvantage of this method is that the maximum duration of the silence instrument is only 60 seconds, so if you want a longer silence you’d either need to use multiple silence instruments or a different method using timeline logic.