How to refresh data in Dynamic product groups

It’s very intuitive and easy to add a dynamic product group that match a filter,
but what I dont understand is how do I refresh the content?

For example I add a dynamic product group with at filter „release date is less than 30 days“ and it matches 10 products, If I then add more products that have release date is less than 30 days. I guess the dynamic groups is cached when created but surely this can be refreshed via API?

In theory: if you add or edit a product and it matches the dynamic group, then the dynamic group should get updated. It does not matter if you add or edit the product via the backend or api.

With caching: I guess theory does not work here. In the backend there is a option to update the indexes in the Cache section. Just look at the XHR, that gets called.