Crystal Reports with Asp.net

Hi,
I am having a requirement in asp.net.
I am using ASP.NET with Crystal Reports.
I am fetching 3 Data sets from Data base. Each Data set having common key field is Employee number.
First Data set kept in Header section. Having Employee details
Second Data set kept as sub report having other inforamtion
Third Data set also a Sub report related to emp info.

Second and Third sub-reports how to link with First Data Set (Header section Report).
URGENT