"in their nature" or "in their natures"?

Each person in the group that comprises 'they' has a different nature ... so the accurate choice should be natures.

I think the group has a group nature.

It's okay. I get a lot of disagreement on this.

I disagree. For example, my nature is easy-going. Other members may not share this quality, as that are not easy-going. Hence they do not share a commonality of nature.

However, there are some qualities of human nature that are in common, but it cannot be stated as an absolute or blanket statement.

So my choice is "It is in their natures to ..."

The singular is more collo