Crystal Reports - Passing a current value of grouping field into a subreport as a parameter

1. Right-click on your subreport. Go to the Change Subreport Links submenu.
2. Drag your field from the left menu to the right.
3. Unselect the Select data in subreport based on field: option.
4. Go into your subreport. Your field will appear in there as a parameter field.
5. Place Parameter Field on Sub Report
6. Right Click on Paramter Field in Sub Report and Click Find In Formula 
7. go into Selection Formulas 
8. go into Record Selection 
9. Match Condition as per requirement like {pro_Dtl.Entry_Id} = {?Pm-pro_Hdr.Entry_Id}