I have .screenrc_im

  source ~/.screenrc
  sessionname im
  bind ^D eval 'at naim stuff "/away Detached!\012"' 'at irssi stuff "/away Detached!\012"' 'detach'
  bind d eval 'at naim stuff "/away Detached!\012"' 'at irssi stuff "/away Detached!\012"' 'detach'
  screen -t naim naim
  screen -t irssi irssi

and a bash alias

  alias im='if detached im; then screen -S im -pirssi -X eval "stuff /away\012"; screen -S im -pnaim -X eval "stuff /away\012"; screen -r im; else screen -x im; fi;'