Hi Aditya,
Thank you for using Syncfusion products.
You can have multiple childs for one parent table by creating and adding the relations.
Below is the code snippet:
DataSet ds = new DataSet();
ds.Tables.AddRange(new DataTable[] { parentTable, childTable, grandChildTable });
ds.Relations.Add(new DataRelation("ParentToChild", ds.Tables[0].Columns["parentID"], ds.Tables[1].Columns["ParentID"]));
ds.Relations.Add(new DataRelation("ChildToGrandChild", ds.Tables[0].Columns["parentID"], ds.Tables[2].Columns["ParentID"]));
this.gridGroupingControl1.DataSource = ds.Tables[0];
Here is a sample that illustrates the same for your reference:
http://websamples.syncfusion.com/samples/Grid.Windows/Grid_WF_GGCMultiChildTableI48002/main.htm Please let me know if you need any further assistance.
Regards,
Jisha