We don't want default selection of any radio button!

Hello,

I placed a RadioButtonGroupByIndex (RB Group by INDEX) UI element on my_view and as I populated with 4 entries, hence am seeing the 4 radio buttons on my_view, also wrote a underlying action w/ name of my_rb_selection_action well, but by default standard SAP is selecting the 1st radio button, but in our case, we don't want to have any default selection of any radio button, we need to force the user to select one of the radio button among 4, so that there is a guarantee of triggering of my underlying my_rb_selection_action

Pls. let us know how we can achive of our requiremnt of no dafult selection of any radio button, all should be open

Thank you