Awk, filtering match through external command

[T o n g <mlist4suntong@yahoo.com>]

Hi, 

Awk allows reading results from external command:

 cmd | getline result

However, I want the cmd itself a piping command as well.  E.g.., 

 "echo " substr($0, RSTART, RLENGTH) | command external with parameters| 
getline result

Any way to make it works?

Thanks