Most SAS procedures (including the Graph procedures) support WHERE statement processing.
Just as you can do this with PROC PRINT:
proc print data=sashelp.class;
where name = 'John';
proc print data=work.fruit;
where fruits = 'Apple' and
year(month) = 2007;
So will the SAS/GRAPH procedures use WHERE statements (or WHERE= data set options)
to allow you to send only a subset of observations to the procedure.