Thanks for your update.
We could not understand your requirement clearly. Could you please confirm you need to show the same caption text in all group, like in the below screenshot? You can achieve this by using SfDataGrid.GroupCaptionTextFormat property. Please refer the below code example
SfDataGrid.GroupCaptionTextFormat = “GroupCaptionText”;
Also you can achieve this by using Converter in GroupColumnDescription. We have update the sample for this in our previous update, please refer it.
Or you need to freeze the caption row of a group at the top until the group records are completely scrolled out of the view and then replace the frozen caption row with the caption row of the next group? In the below screenshot we have mention about GrouCaptionText and group records.
If your requirement is deferring from this, could you please share screenshot based on your requirement, that would be more helpful for us to serve you better?