Is this possible?

Users will enter records of work into a GeneralEntry spreadsheet. Each
record includes a Client field, which they fill using a dropdown. Records
are entered as work is completed, so client rows are not grouped together.

A set of additional worksheets, one for each client, automatically display
only the rows from GeneralEntry which contain the client's name in the
Client field. Each of the client sheets should perform summary calculations
on just the rows appearing in the client sheet, and display the results
above the detail rows.

I have tried using filtered lists on the client sheets. That works fine for
displaying only the desired client's rows from GeneralEntry.

However I can't figure out how to create summary calculations that will use
only the displayed rows. The number of rows varies, so summary calculations
on a range of cells which might display data are required. But using
filtered lists, summary calculations on the hours range, for example,
produce the total of all hours in GeneralEntry rather than the total of the
visible rows in the client sheet.

Thanks in advance for any ideas, advice, etc