drag formula and skip blanks rows

Hi,
my first post here, it looks like a really useful and used forum!
i'm working with a spreadsheet, 6 tabs. On each tab, column A is the date. In the first sheet, i want to get the total from the 5 others for each day. Would be damn easy except that:
- in the first sheet, all the rows are "populated", no blanks between the dates
- in the 5 other sheets, there is a blank row between each date.
Therefore, if i only enter the formula "= sheet 2 + sheet 3 + sheet 4..." i end up with 0 values for every second day.
How can i drag the formula and at the same time skip the blanks that exist in the sheets where i'm getting my data?
i know i can probably use Vlookup, look up the date for every day and sum the corresponding values in each sheet, but i'm looking for something "fancier" adding a blank row between each day in the first sheet is not really an option right now either!
Thanks a lot!