Option for a portfolio to pull in other portfolios without having to mirror each item

Description

We have multiple portfolios per domain with many projects in each and a constant flow of new items added.
We would like the option to have a higher up portfolio that automatically pulls in multiple other portfolios for a overarching view of all the smaller ones.
We have tried the mirroring a portfolio in a dashboard but the window does not expand enough so it crops off from a certain point. I know you can expand the window but it is a bit clunky.

What are you trying to achieve

A higher up level portfolio that can pull in normal portfolios

Agree, it is difficult to provide an aggregated view of portfolios, they are very much siloed. I have a related feature request for portfolios nested under portfolios that’s worth upvoting/checking out: