How to define automatic filter condition?

Hi All,

--PG8.3
--Windows 2k3 SBS

I would like to apply an automatic filter condition to a table. I create a
TEMP table at the beginning of the session to store a value to build up a
filter condition and I would like to apply this condition to every select
statement to a table during the current session.
I know that I could use views but views are read only and I also need Update
and Insert.

Could anybody turn my head to the right direction?

Thank you,

-- Csaba