Currently, load frequency control (LFC) in Japanese power systems is carried out in the individual control areas, and the control signal is allocated to regulated generators based on their ramp rate (RR method). In the future, a wide-LFC-system will be implemented and the LFC signal will be created by merit-order of the generators (MO method) instead. However, this approach is result in increasing frequency fluctuations. Moreover, when remote generators are controlled for the wide LFC, the tie-line available transfer capability (ATC) of the interconnection lines have to be taken into account for the LFC signal creation. To address these challenges, this paper proposes an LFC signal dispatching method that decomposes the Area Requirement (AR) signal in a layered manner to benefit from the advantages of both the RR and MO method. A simulation study shows that the proposed method has a potential to achieve both economic efficiency and frequency stability under the ATC constraints.