A hydraulic two-circuit system (2, 4) for activating consumers (A1, B1; A2, B2; A3, B3) of a mobile unit, for example a track-laying unit, and an interconnecting valve arrangement (38), which is suitable for a two-circuit system (2, 4) of this type and via which the two circuits (2, 4) can be interconnected so as to add them together, are disclosed. According to the invention, the interconnecting valve arrangement has an interconnecting valve with two pressure connections (P1, P2), two LS input connections (LS1, LS2) and two LS output connections, wherein a valve body of the interconnecting valve is designed with four control surfaces, of which two control surfaces which act in one direction are acted upon by the highest load pressure (LS1) in the first circuit and by the pumping pressure (P2) in the second circuit, and the control surfaces acting in the other direction are acted upon by the highest load pressure (LS2) in the second circuit and by the pumping pressure (P1) in the first circuit.