they won't work like it sounds like you think they will.
All tone coded squelch does is keep the radio silent until it thinks it hears the correct tone. Once it opens, you will hear whatever may be on that frequency. It also does not prevent them from hearing you.
So, if you and another in your group set a DCS code, and one of you starts talking, but skip is harsh that day, you will only hear AAAAAAUUUDDIOOO AAAAAAAAUUUUUUDDDDIIIOOOO.
It also doesn't help with wideband splatter once the squelch drops, too.
If that IS what you meant, you guys stay close together, use good antennas, and set the squelch very high, you're right. Might work out just fine.