allowing users to change the IP-addresses that are allowed to connect to postgresql

[stig erikson <stigerikson_nospam_(at)yahoo(dot)se>]

Hello.
I have a postgresql 7.4.5 running.
On the server i have a few databases, all owned and administered by 
different users.
The users sometimes change access-rules to their databases, in 
particular they change access rules based on IP-addresses, which i have 
to do for them manually in pg_hba.conf.

is there some way to avoid the pg_hba.conf-file?
optimally i would like the access rights to be stored with the user 
and/or the database and tables. is this possible?
thus allowing users to change access rights themselfs.

if it is not possible in 7.4.5, is it planned for 8.0?

/stig