It is not possible in PLD 'as is'
but
I made the following workaround:

1. Run SQL with unique comment

Code
select /*mycomm*/ * from dual

2. Run XPLAN

Code
select * from table(dbms_xplan.display_cursor(sql_id => 
          (select sql_id from v$sql 
                  where upper(sql_text) like '%/*MYCOMM*/%' and upper(sql_text) not like '%/*MYCOMM1*/%'),
          format => 'ADVANCED')
   )