Is there a way to get all selected checkboxes?

I don't have the software at hand to try now. 

I was thinking about creating true and false variables as monitors, but I wonder if it is possible to

When user click feedbackButton, set state of checkbox 1 to hidden

if state of checkbox 1 is not selcted;

or

When user click feedbackButton, set value of (new) variable customFeedback to [custom text value]

if state of checkbox 1 is selected and/or state of checkbox 2 is selected;