I came up with a way to deal with this. My example is a list of open sales orders where I'm subtotaling on open dollars at each change in Sales Order Number, but iI want to be able to see the customer name in the subtotal information. So here's what I do.

After you use the subtotal function, expand the selection so all lines are visible. Go to the column that you want displayed in your subtotal. Highlight the whole column. Go to "Find & Select" and choose "Go To Special". Then choose "Blanks".

Once the blank cells are selected, don't click anything or you'll have to select all over again. Your cursor will automatically be placed in the first blank cell. Simply start typing =b2 (or whatever the cell is immediately above your first blank). Then, hit Control + Enter. This will copy the formula to all the blank cells in the column.

Now, when you shrink your selection to the Subtotal Lines, the information from the other columns will be visible.