Thanks for clarification. As I mentioned, I've never used a bnc, so wasn't sure what was different.

As far as the last line in that quote, you can do that with mIRC. Not positive if that's going to work the same in a bnc.

Open a channel and minimize it. Right click on the channel in the switchbar/treebar and choose Position > Set as default. New channels joined will open minimized. You may need to clear out any channel settings from mIRC.ini in order for channels you've been in before to open minimized as those may have their own settings already that Set as default won't override.