Using dsum across sheets

[Mike Perry <mikepery fscked org>]

Is it possible to use the DSUM function on values from two different
sheets? For example, I am trying to write something like:

=DSUM(Timetable!A1:Timetable!F45, Timetable!F, A1,A17)

This formula occurs in a sheet called "Jobtable". A1 and A17 of Jobtable are:

  
1   Job #
2     1
3     2
4     .
5     .
17    16

Timetable has a bunch of columns and rows, but the important ones are:

    A        .... ...   E       F
1  Date      .... ... Job #  Time Delta 
2 1/22/04               16      0:30
3   .
4   .
5 1/23/04    .... ...   16      0:15


The idea is to take all jobs that match the given job number and sum
their time duration. 

The problem is Gnumeric complains about the DSUM function being an
Invalid Expression.. I tried doing something like A1:A2 for the third
argument, but that's not really what I want, and gives the same error as
well.

Is what I'm trying to do even possible? Am I just doing it wrong?

-- 
Mike Perry
Mad Computer Scientist
fscked.org evil labs