How to do common pipelines?

[Dr. Bhatia Praveen]

Hello,
  Would like to use a pipeline, p,  which is commonly used by other 
pipelines, p1, p2, p3.

  How could one achieve in p1, a call to common pipeline p, and then 
continue the processing into pipeline.
(It sounds more like a functional call. In function parlance, it is 
equivalent to a function calling another function within itself and 
continuing forward after the function returns).

Thanks