Running a script in runlevel 1

hi all
i have to run a script in run level 1 automatically i.e when i give init 1 from runlevel 3 that script should run after entering into runlevel 1.
where can i put that script so that it will run as i said above..???

something similar to rc.local but this will run in runlevel 3( correct if i'm worng)..
any script like rc.local for runlevel 1....?

/etc/init.d with a link in rc1.d