As far as I know, we cannot make the RadGrid rows as static. The only content, which may be kept frozen (static) is the header, command item, pager and footer, if you enable scrolling with static headers as described in the forum
One workaround is using HeaderTemplate for the columns and use row like structure. Add labels inside HeaderTemplate and set the Text property of Label accordingly (as the cell value of first two rows). Set UserStaticHeader property to True. And then hide the first two rows in RadGrid.
Hope this suggestion helps.