A subreport is independent of the main report, by default.
You can then limit it in various ways:
a) Put the same selection formula into the subreport, using cut-and-paste to copy the commands
b) Put the subreport in a detail line, and use subreport links under edit to pass the account number (or whatever). This is useful when you want to associate subreport data with the details, but is also slow
Madawc Williams
East Anglia, Great Britain