Hi Nick,
Thank you for your interest in Syncfusion products.
We suggest you to add the HyperLink to any GridGroupingControl using the ItemTemplate. For more details please refer our online samples at the below link.
http://samples.syncfusion.com/ASPNET/7.4.0.20/Web/Grid.Grouping.Web/samples/3.5/Summary/PortFolioGrid/cs/portfoliogrid.aspx?args=11Refer the link below to create an ItemTemplate.
http://help.syncfusion.com/ug_74/gridweb/CreatingTemplates.htmlRegards,
Jaffer.B