There are a couple of weird things here.

Are you sure you want to create an array of QGroupBox in onaddbutton_clicked()?
What exactly are your plans for the QSIgnalMapper?

Not sure why you are wondering that btnTest adds things to all groupboxes, after all you connect it that way.

Also no "emit" int that lambda, systembutton_clicked() is not a signal.

Cheers,
_