2012 a/c,heater control question

:banghead:ok I know some or most of you may think this is silly, but its driving me crazy !
This is my first dodge in a long long time, the recirculate button only works in certain settings,right?
I want to be able to keep it in recirculate all the time, how can I do this? No matter if I have it on defrost or any setting.
Help....