Thanks for using Syncfusion product.
Please refer the dashboard sample “Database Diagram” in “Use Case Diagram” category which demonstrates the method of adding multiple nodes to group node. You can also find the sample in the below location:
../../AppData\Local\Syncfusion\EssentialStudio\18.104.22.168\Windows\Diagram.Windows\Samples\Use Case Diagram\Database Diagram
You can also run the samples through dashboard using the below steps:
Run the Dashboard->Windows Forms->Diagram->UseCaseDiagram->Database Diagram
Thanks for your update,
We are happy to hear that the issue has been solved. Please let us know if you require any further assistance on this.