Create a group and position it at point x/y.
Then, have an object set to conditionally appear if that group is hovered (e.g., a 1px by 1px text element without any text in it). Then, set a work-flow to display the pop up when the object appears.
Note - the reason to include the object and not reference the original group is because it'll appear on hover then disappear after the user hovers away. Abstracting it one step enables you to have the object appear permanently once the original group is hovered once.