This is not possible - you are addressing the symptom rather then the cause.
Have you determined what process is leaving sessions open in the database? Why don't you increase processes and sessions so the applications will not crash or run out of sessions?
Is your EBusiness Suite licensed by concurrent number of users? If not, then what you are doing sounds like a band aid solution for limiting sessions. There are better ways of limiting sessions via database parameters, and controlling environment variables in application tier node for forms times outs (e.g. FORMS_TIMEOUT).
However, I once came across the following metalink note - I have not tried it and am not sure how it would behave with EBusiness Suite :
How to Set the Maximum Number of Forms Sessions on the Application Server (Doc ID 125539.1)
Might want to change the cursor sql logic in the above note depending upon what your forms processes show up as e.g. for me it will be:
select count(*) sessions from sys.v_$session
upper(program) like 'FRMWEB%'
I would also suggest (if your OS is Linux/some sort of Unix, etc.) do a 'top' in the application tier node and see if there are processes putting huge load on your system and actually 'left over form sessions'. Terminate those processes.