Allow choosing status by group

Hi,

here is there a feature I always wanted to find in IMs.
I want to allow only certain group(s) to:
1- see me as visible/away/busy/etc...
2- to send me messages

Maybe point 1 is not possible due to the protocols or the relative IM service providers (MSN, Gtalk, etc...), but point 2 could be implemented on the software side, since it boils down to filter out messages from contacts that are not in the defined groups.
So the idea would be to be shown as invisible, but still receive the messages and only show/notify the ones that are allowed by the selected contact groups.

Please let me know if this possible at all, or if it is already possible but with only some of the protocols.
Thanks.

Renaud