Excel 2003

I have a spreadsheet that has groupings
           col a        b            c            d
row 1     2                                     sum(r2:r5)
row 2     1        =a2*a1
row 3    2           =a3*a1

If I want to copy the whole group -with the formula in Column B I can copy
the whole group (Row 1 to Row 3) and Insert Copied Cells and all is fine.

If I want to insert rows into the group then the column B formula changes to
a3*a2 (for eg)

If I change the formula in column b to a2*$a$1 I can insert rows within the
group ok but if I copy the whole group the new group is still looking at
cell A1

How can I overcome this problem - is there a way of perhaps naming the top
row of the group so that when the group is copied the formula always looks
at the top line of the group?

Thanks