Here are some alternative ways to express "No divvies allowed": No sharing allowed. Sharing is not permitted. Do not split the items. Keep the items to yourself. Individual use only. Do not distribute. No dividing the items. Items are for personal use only. No splitting or sharing. Keep your own portion.

I had to look that one up. Apparently, it's a British slang word used to describe really stupid people. The two closest commonly used American slang terms I can think of both have curse words that wouldn't get past the moderation filters here (dip***** and dumb *****), so I'll just suggest "morons" and "idiots" as the closest equivalents that I can share here in the community questions.