Thank you for writing.
The attached sample project illustrates one possible implementation of the desired scenario. The project contains a RadGridView with three ChildTemplates added to the MasterTemplate. Using the ViewCellFormatting
event you can specify which tab to be selected when the user expands a row. For details please refer to the attachment.
I hope you find my answer helpful. If you have any questions do not hesitate to write back.
the Telerik team