I have multiple portfolios (xml files). Is there any way to merge them into one portfolio? Or to just see a combined overview or summary report of all the portfolios together?
No, that isn’t possible. You can, however, split the window and see two files next to each other.
The other way 'round works, with filters you can limit your view to exact one of multiple accounts – so merging the two might be an option depending on how much work that would cause.