The azimuthal order of a hexatic liquid crystal bounded by two parallel borders in a field applied perpendicularly to the two interfaces is theoretically discussed and an anchoring-dependent phase separation is predicted. It is found that periodical or exponential-type phase separation along the direction of the applied field occurs at a series of favourable lengths associated with anchoring strength, susceptibility anisotropy, nematic as well as hexatic orders. Deviation from the favorable length may invoke a pair of sheet disclinations at the boundaries, which will shift to the middle of the cell in order to substain the harmony between dimension and anchoring.