[O] tables: sum columns only in certain ranges of rows

[Uwe Brauer]

Hi

Is the a simple way to tell a org-table that
it adds say two columns in a certain way $4=0.2*($2+$3)
but only for certain values of the row. I hoped that 
a hline would help but it does not the row containing Taylor
is treated in the same way as row 1 to 4.




| Row | Name   | E1 | E2 | Res |
|-----+--------+----+----+-----|
|   1 | Smith  |  1 |  2 | 0.6 |
|   2 | Miller |  2 |  1 | 0.6 |
|   3 | Meyer  |  1 |  4 |  1. |
|   4 | Wilson |  2 |  1 | 0.6 |
|-----+--------+----+----+-----|
|   5 | Taylor |  1 |  2 | 0.6 |
|-----+--------+----+----+-----|
#+TBLFM: address@hidden::$5=0.2*($3+$4)


So what is the most comfortable to obtain what I want?

Thanks

Uwe Brauer