Multi reference automatically linked both ways

We have a travel website - https://www.geekyplanet.com/. We have collections for countries, areas of natural beauty, animals and plants.

On each collection there is a multi reference filed for each of the other collections. So for example on Where can I see the African Lion in the wild, I have tagged all of the countries that the african lion can be found, along with the areas of natural beauty.

The problem I have is that I then need to go into the country collection and for each country tag the african lion. It’s just incredibly time consuming.

Is there a way that you can link two multi-reference fields. So for example if I added a new animal and added all of the countries that it will automatically add that animal to each of the countries.

Any help would be appreciated. It was fun adding the first round of content, but as we add more it’s only getting more complicated.

Thank you.