The only option that I see for this in the Settings is the 'Block / allow applications'. It has a list where you can add your apps. And a checkbox to 'Only allow specified applications to be in a Group'. Am I to assume that if that checkbox is unchecked, then Groupy will Block the list of apps from Groupy grouping them?
It's weird that there are not just two radio buttons(mutually exclusive). (o) Allow (o) Block
It's just not clear, when it could be.. It's just weird that you present 2 choices in the title, and only display 1 checkbox for 'Allow'. I have to assume the answer is it will Block.