all possible pairwise combinations for specific companies in a specific year and in a specific country without repitition

[Maysam Ayoub]

Hello,
I would like to find all possible pairwise combinations for specific companies in a specific year and in a specific country.

YEAR	COUNTRY	AUDIT FIRM	CITY
2012	Belgium	EY	Brussels
2012	Belgium	EY	Antwerp
2012	Belgium	EY	Liege
2013	Belgium	KPMG	Brussels
2013	Belgium	KPMG	Antwerp
2013	Belgium	KPMG	Liege

so that the result is in this format

YEAR	COUNTRY	AUDIT FIRM	CITY	CITY1	CITY2
2012	Belgium	EY	Brussels	Brussels	Antwerp
2012	Belgium	EY	Antwerp	Antwerp	Liege
2012	Belgium	EY	Liege	Liege	Brussels
2013	Belgium	KPMG	Brussels	Brussels	Antwerp
2013	Belgium	KPMG	Antwerp	Antwerp	Liege
2013	Belgium	KPMG	Liege	Liege	Brussels

Appreciate your help