Is there any method of prohibiting the use of specific default emojis (such as regional_indicator emojis) as reactions, without completely disabling all reactions?

Is there any method for prohibiting the use of regional_indicator emojis as reactions, besides completely revoking reaction permissions?

I don't trust the users of my server to *not* attempt abusing those to flood my server with slurs and such using those emojis (and they have already attempted doing that, leading to reaction permissions being revoked for everyone so it doesn't happen again), but I don't want to prevent the use of reactions for those who aren't abusing them.

Being able to simply prohibit certain default emojis being used as reactions (such as regional_indicator emojis) would solve this issue, but I don't know if it's possible to do that, or how to go about doing that.

Please advise.