Hi
yes you can you need to link the 4 subreports
right click individual subreport reports then select change subreport links in
Field(s) to link to move you start date and end date from Available Fields ,it will create a subreport parameter ?PM---start date and so on in Subreport Parameter field to use then go to your individual subreports and check the ?PM parameter with the date field/s in your subreport.
You can also create formulas in your main report for start date and end date and then link them in your subreport ....
Cheers
Rahul