Is your dataset source from table or SP? If you can add rownumber in your dataset source you can just add a filter in your detail group. select the rownumber...

You cannot add tablix in report footer. As work around you can add a tablix in the bottom part of the report body, hide it if not the last page....

Thanks Daniel. This works. Just need a little workaround with the design .

If the fields you need for your report is coming from different SP you can use multiple dataset. Or you can create new SP that contains all the your required...