A link can have multiple from/toPort

As can be seen from the figure, can link have multiple from/toPort?

I cannot tell from your screenshot what it is that you are trying to show.

Links cannot have ports – only Nodes can have ports.

But you can associate a Node with a Link, by having one or more Nodes as “label nodes” on a Link. See Links to Links.

Or maybe you really want to have links connect with a really long thin node: Network Configuration

Thank you very much. This is a very useful example. I need to test it.
Is there any alternative to this?I want a link to connect multiple nodes.

I have no idea which sample you are talking about.

A,B,C and D are connected by A red link, which means that the red link has multiple nodes.

If one were able to select the link and delete it, would all connections be lost? Or could one delete only the connection with (for example) “A”, keeping the connections between “B”, “C”, and “D”?

I hope that if I delete A, then B, C and D are still connected.

It would be easiest to implement something like the BarNode in the network sample that I mentioned above: Network Configuration.

That way users can draw and delete each connection (i.e. each Link) independently. Or select and delete the BarNode to delete all those connections.