Problem:
Need to determine the total number of days to process a product, including
the number of days each section took to do their part.
Column "D" is actually one cell providing a SUM of C1:C4.  
    Cells D1:D3 displays results in this one cell (Process Days)

Part 1:
Holiday: 05/26/08

       A        B              C                             D
1    Date In    Date Out    NETWORKDAYS    Process Days
2    05/01/08    05/15/08             11                            11
3    05/16/08       xx         -28273                       ###
4     xx    06/10/08          28289                            27
5               

Problem 1:  
   Cell D2 provides the result needed.
   Row 3 -Cell C3 - Needs to read "Date Missing" until B3 "Date Out"
provided.
   Cell D3 - Needs to read "Date Missing" until B3 "Date Out" provided.
   Row 4 - Cell C4 - Needs to read "Date Missing" until A4 "Date In" is
provided.
    Cell D4 I believe, is giving the SUM of C1-C2+C3.  Needs to read
    "Date Missing" until B3 and A4 provided.

    Is this possible?  If so, would you please provide guidance?

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Part 2

       A        B              C                             D
1    Date In    Date Out    NETWORKDAYS    Process Days
2    05/01/08    05/15/08             11                            11
3    05/16/08       xx         -28273                       ###
4     xx    06/10/08          28289                            27

                A              B                  C               D        
      E
              Sect      Sect Resp    On Hold     Off Hold    Days on Hold
20                   
21    A               
22    B    A    05/05/08    05/08/08    4
23    C    A    05/21/08    05/27/08    5

Problem 2:    This added to #1 above.

During Section B's and Section C's processing, the product was returned to
"Section A" because they missed something.  Sections B/ placed their "process
on hold".  I need to add the days on hold to Section A's processing time.  
Cells E22:E23 (4+5 days) to be added to C2 (11 days) for a total of 20 days
(I can add another cell/column/row for this number).

    Again, is this possible?   I'd really appreciate any help.