This got me the idea how to proceed. Thank you very much.

You can make a list of GameObject and when they're instantiated (Instantiate a prefab) you add them to the list. To destroy the objects you can use a loop inside a coroutine, like:

IEnumerator destroyMyObjects(System.Collections.Genenic.List<GameObject> whichObjects, float delayBetweenDestructions) {

for(int i = 0; i < whichObjects.Count; i++) {

Destroy(whichObjects[i]);

yield return new WaitForSeconds(delayBetweenDestructions);

}

}

Make sure to call the method with StartCoroutine just one time.

You can make the list of Game Objects a static list so you can add in to this list from any other script.