Easy Peasy by using Action :D
-> Open Action panel by Hitting Alt + F9.
-> Create a new action and don't forget to assign a shortcut key (currently only functions keys along with Shift/Ctrl is allowed and you can change this anytime btw if you use script then you can assign any keys!)
-> just record following steps like i did while record (red colored dot) is on and stop when you complete following step and you're ready to go!
-> the steps are : Duplicate group; Merge Group; Selection; Delete Current Layer.
or below is the script, if you want to assign another shortcut then save this script.
//duplicates group
app.activeDocument.activeLayer.duplicate(app.activeDocument.activeLayer,ElementPlacement.PLACEAFTER);
// merge
app.activeDocument.activeLayer.merge();
//set selection
var idsetd = charIDToTypeID( "setd" );
var desc7427 = new ActionDescriptor();
var idnull = charIDToTypeID( "null" );
var ref1300 = new ActionReference();
var idChnl = charIDToTypeID( "Chnl" );
var idfsel = charIDToTypeID( "fsel" );
ref1300.putProperty( idChnl, idfsel );
desc7427.putReference( idnull, ref1300 );
var idT = charIDToTypeID( "T " );
var ref1301 = new ActionReference();
var idChnl = charIDToTypeID( "Chnl" );
var idChnl = charIDToTypeID( "Chnl" );
var idTrsp = charIDToTypeID( "Trsp" );
ref1301.putEnumerated( idChnl, idChnl, idTrsp );
desc7427.putReference( idT, ref1301 );
executeAction( idsetd, desc7427, DialogModes.NO );
//remove layer
app.activeDocument.activeLayer.remove();