to point a selfwritten class in the inspector (drag n drop)

Hi community, to set up a dialog system I want a class (dialogPoint -> shown text and options to say) that contains a list of other dialogPoint objects, which will be used to jump to a new point if you select what you want to say. The problem is that I want to have two different "inspector-types" of a dialogPoint variable: One to modify and the second to point/link to an modified one. So, how can I tell the script that I want to modify the following variable or that the inspector should let me drag n drop something to this variable?