MicrosoftYou were at the top of my list of those I was going to contact by email before committing a post to UserVoice.
I think the management of arrays of arrays (or arrays of ranges) is very closely related to your SUMROWS and SUMCOLS functions. I think such functions cover most of the requirement and offer an easy win. Despite that, I think the arrays of arrays issue is one that is worth getting right because potentially it applies to just about any function. Here I wanted to return an array of ranges using XLOOKUP and then conditionally aggregate each range with SUMIFS to obtain a row of totals. I would appreciate any further thoughts you may have. Meanwhile I will try your SLICES function; I assumed it returns arrays rather than references but some experimentation is called for.
You seem to have a flair for achieving the impossible ! 
I don't know what made you think of INDIRECT, but it works perfectly to give an array of ranges.
Following your idea, I also tried
= SUMIFS( EVALUATE( "Table1[" & Table1[#Headers] & "]" ), Buyer, Payee )
which works as a named formula.
SergeiBaklanThank you for the offered support. I will try to put something together over the next few days.
