Excel: Find intersection of a row and a column

Excel: Find intersection of a row and a column

My question is how can I find an intersecting cell of a specific column
and row number?
My situation is this: with some calculations I find two cells, lets say B6
and E1. I know that I need a row of the first one and a column of the
second one. So I could just use ROW and COLUMN functions to get the
numbers. After that, I need to find an intersecting cell. Which would be
E6 in this example.
I would just use INDEX(A1:Z100;ROW;COLUMN) but I don't know the exact area
that I'm going to need - it depends on other stuff. I could use something
like A1:XFG65000 but that is way too lame. I could also use a combination
of INDIRECT(ADDRESS()) but I'm pulling data from a closed workbook so
INDIRECT will not work.
If this would help to know what is this all for - I need to do some stuff
with a range. It's top left corner would be B1. That B6 would mean the
bottom left corner and E1 - top right. And now, to process this range, I
need to define it as B1:E6 - so I need to know the bottom right cell,
which is intersection of a ROW and a COLUMN that I'm have already found.
There's got to be a decent way to do this, but I've been thinking for a
while now and not being and Excel expert - I couldn't come up with
anything. So any help would really be appreciated. Thanks!