How to create merge cell on rows with crosstab?

[testmachii]

Hi,

I am having the issue to create the merge cell over rows while exporting the report to xls format through Jasper server. The report is not creating the merge cell for rows intead it showing under the single row.

I want to show the merge cell row header as per below Image (SIGN-UP Month), I am using the crosstab to display the data. I have applied various method and used properties available, to fix this. When I generate the report directly from the Jasper Studio its working fine but did not work when export through Jasper Sever.
Help me to find out the solution and fix this.

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