The feature is not built-in in MG-Picker Studio.
In theory, you can do that using command python API. The idea will be to get the currently selected button id in picker view (cmds.MGPickerView(q=True, select=True)), grab the Maya selection (cmds.ls(sl=True), and use cmds.MGPickerItem(theId, selectMembers="nodeDagPathsJointBySpace") to set the object list.
And you save the script as run time command in Maya and attach a hotkey using the Maya hotkey editor. But the thing is, MG-Picker Studio already occupy many hotkeys in designer UI mode, so if you have the UI activated, you need to use a hotkey that is not occupied.