Hello Mario
To create plugs, there is no boolean type option!
One possibility is to duplicate the end of your graph by replacing the circle with a full disk, and test if it is the first or the last copy, “switch” on the full disk, otherwise “switch” on a node “null”. You must activate the “use iterator” of the “copy using vector” node.
Here is an image of the graph:
And the link.
https://creator.trimble.com/graph?layout=right&assetURI=whp:3efa0a24-9110-4d1a-bf51-702c9907b587
Surely there is another way!
Simon