auto move to another usergroup

[squawell]

is there have any hack can do like title say??

i mean !!if user in some condition than the system will move they

to another usergroup??

for example:

i made a new usergroup call- banned

when user not posted for month ago than system will auto move

they to the banned usergroup!!

any idea??or the hack already existed~~

[squawell]

any idea??

i need this hack!!

plz hlpe me