An assembly of a concealed sanitary fitting comprising a) a connecting member for installation in an installation recess of a sanitary installation, comprising - connection pieces (14a, 14b, 14c, 14d) for connection with a pipework of the sanitary installation and - a first connection interface comprising first connection openings (20a, 20b, 20c, 20d) which are connected to the connection pieces (14a, 14b, 14c, 14d), b) a valve function unit comprising - a first counter-connection interface, wherein the first counter-connection interface comprises first counter-connection openings (33a, 33b, 33c, 33d), c) a water passage diverter element which comprises - a second counter-connection interface and - a second connection interface, wherein - the second connection interface comprises second connection openings (48a, 48b, 48c, 48d) and the second counter-connection interface comprises second counter-connection openings (52a, 52b, 52c, 52d), wherein the second counter-connection openings (52a, 52b, 52c, 52d) are connected with the second connection openings (48a, 48b, 48c, 48d) via internal water passages (60, 62) and wherein - at least one of the second counter-connection openings (52a, 52c) is connected with a second connection openings (48c, 48a) that is not aligned with the at least one of the second counter-connection openings (52a, 52c) characterized in that d) the first counter-connection interface of the valve unit is complementary to the first connection interface of the connecting member and the first counter-connection openings (33a, 33b, 33c, 33d) of the first counter-connection interface are for connection with first connection openings (20a, 20b, 20c, 20d) of the connecting member, e) the second counter-connection interface of the water passage diverter element corresponds to the first counter-connection interface of the valve function unit with respect to the interface geometry and f) the second connection interface of the water passage diverter element corresponds to the first connection-interface of the connecting member with respect to the interface geometry. a) a connecting member for installation in an installation recess of a sanitary installation, comprising - connection pieces (14a, 14b, 14c, 14d) for connection with a pipework of the sanitary installation and - a first connection interface comprising first connection openings (20a, 20b, 20c, 20d) which are connected to the connection pieces (14a, 14b, 14c, 14d), - connection pieces (14a, 14b, 14c, 14d) for connection with a pipework of the sanitary installation and - a first connection interface comprising first connection openings (20a, 20b, 20c, 20d) which are connected to the connection pieces (14a, 14b, 14c, 14d), b) a valve function unit comprising - a first counter-connection interface, wherein the first counter-connection interface comprises first counter-connection openings (33a, 33b, 33c, 33d), - a first counter-connection interface, wherein the first counter-connection interface comprises first counter-connection openings (33a, 33b, 33c, 33d), c) a water passage diverter element which comprises - a second counter-connection interface and - a second connection interface, wherein - the second connection interface comprises second connection openings (48a, 48b, 48c, 48d) and the second counter-connection interface comprises second counter-connection openings (52a, 52b, 52c, 52d), wherein the second counter-connection openings (52a, 52b, 52c, 52d) are connected with the second connection openings (48a, 48b, 48c, 48d) via internal water passages (60, 62) and wherein - at least one of the second counter-connection openings (52a, 52c) is connected with a second connection openings (48c, 48a) that is not aligned with the at least one of the second counter-connection openings (52a, 52c) characterized in that - a second counter-connection interface and - a second connection interface, - the second connection interface comprises second connection openings (48a, 48b, 48c, 48d) and the second counter-connection interface comprises second counter-connection openings (52a, 52b, 52c, 52d), wherein the second counter-connection openings (52a, 52b, 52c, 52d) are connected with the second connection openings (48a, 48b, 48c, 48d) via internal water passages (60, 62) and wherein - at least one of the second counter-connection openings (52a, 52c) is connected with a second connection openings (48c, 48a) that is not aligned with the at least one of the second counter-connection openings (52a, 52c) characterized in that d) the first counter-connection interface of the valve unit is complementary to the first connection interface of the connecting member and the first counter-connection openings (33a, 33b, 33c, 33d) of the first counter-connection interface are for connection with first connection openings (20a, 20b, 20c, 20d) of the connecting member, e) the second counter-connection interface of the water passage diverter element corresponds to the first counter-connection interface of the valve function unit with respect to the interface geometry and f) the second connection interface of the water passage diverter element corresponds to the first connection-interface of the connecting member with respect to the interface geometry.