Mapping with custom rules

[#1]

Hi to everyone,

kindly ask for help!

I have a pivot table like this (example):

SITE	CODE	EXPR1	EXPR2
001	A	1	1
001	B	1	1
001	C	1	0
002	A	1	1
002	C	1	0

My goal is to have something like this:

SITE	CODE	EXPR1	EXPR2
001	AB	1	1
002	A	1	1

So, when, in a Site I have:

CODE                                     NEW CODE

only A (or only B or only C)   -> A

A+B                                    -> AB

A+other                                -> A

I think it's a kind of mapping, and I want to do it in presentation, but I don't know how I can aggr by Site (something with concat function?) .

Maybe the worst is remove , ad example in Site 001, rows with only A (or only B, or C).

Sorry if this is not clear, I don't know how make it easier