I suspect it won't work for your intended application, but here is an answer to your question:
You can't create an array of arrays, because that would be the same as increasing the number of dimensions of the array. However, you can store an array in a cluster, then have an array of clusters with arrays in them. So, indirectly it is possible. This gives you the possibility of each array being a different size.
Bruce
Bruce Ammons
Ammons Engineering