How to capture a portion of record Every line to be processed and print another processed value rather than the actual portion ?

I need to capture a record every new line and put it in a variable and have processing in it returnning to the RPE key the value from processing .

I tried GETFIELD but does not work for as evey line . It works only one per page . Not per line .

As far as I tested I can print variable in RPE key like
this :

[ 0 0 500 null 910 50 0 ($$VARproc.) VSUB /F1 BLACK]

That variable is a result of processing of a record portion saved in another variable named field .

sheet=field/2
if (sheet%3==0 )
tot_env=int(sheet/3)
else
tot_env=(int(sheet/3)+1)

Let me reform my need :
I Have a column that has certain values which I do not want them to be printed like this :
4
6
10
4
6
I need to processs value 4,6,10.... into function and return the value
as caluculate_envelops(4)

function caluculate_envelops(field)
sheet=field/2
if (sheet%3==0 )
tot_env=int(sheet/3)
else
tot_env=(int(sheet/3)+1)
return tot_env

I need to print the tot_env not the field value .