Systems of the CsCoX3 family form antiferromagnetic chains along the c-axis, and are arranged in a frustrated triangular arrangement in the ab-plane. Below 30K, both systems have been reported as forming a partially disordered antiferromagnet (PDA) phase. Recent work on Tb(HCOO)3 demonstrated that peaks in the magnetic neutron scattering, which if treated classically as Bragg peaks give rise to a PDA state, can be interpreted as maxima in the continuous diffuse scattering function, which correspond to a short-range ordered triangular Ising antiferromagnetic ("up-up-down") system. We propose the collection of the diffuse magnetic scattering of these systems in order to determine the nature of the PDA phase. We will require 2 days of beamtime on WISH to complete this study.