It can be possible to puck do the following

Yes, definitely - you just need some code a bit like the following:

var kb = require("ble_hid_keyboard");
NRF.setServices(undefined, { hid : kb.report });

var keyTimeout, keyClicks = 0;

function onClick(count) {
  if (count==1) {
    // kb.tap(kb.KEY["7"], kb.MODIFY.ALT|kb.MODIFY.CTRL);
    digitalPulse(LED1,1,100); // red
  } else if (count==2) {
    // kb.tap(kb.KEY[8], 0);
    digitalPulse(LED2,1,100); // green
  } else if (count==3) {
    // kb.tap(kb.KEY[9], 0);
    digitalPulse(LED3,1,100); // blue
  } else {
    // some other number?
  }
}

setWatch(function() {
  keyClicks++;
  if (keyTimeout) clearTimeout(keyTimeout);
  keyTimeout = setTimeout(function() {
    keyTimeout = undefined;
    onClick(keyClicks);
    keyClicks=0;
  }, 500);  
}, BTN, {repeat:true, debounce:20, edge:"rising"});

That uses a 500ms (1/2 second) delay - so your multiple clicks have to be faster than that. It's easy enough to change though.