you asked for simple, and you got two simple methods...the more you want in it, the more complicated it's going to be, and you really should include all of the options that you want in the first post.

If you don't want the bot to turn the script on/off via pm, how do you want it? in channel, via DCC, or CTCP?

In regards to my script, the group at the start controls if the on open event in that group is recognized or not...if the group is on, then it will be, and it overrides the 2nd on open event.
If the group is off, then the 1st on open event is ignored, and the 2nd one is processed.