Multi-EnerCage-HC (mEHC) system is a wireless experimental arena for high throughput experiments on multiple small freely behaving animals simultaneously, which can significantly reduce costs by saving lab space and cutting the manual labor. However, since each homecage is encompassed with multiple coils, the cross-couplings among the adjacent EnerCage-HC systems cause operating frequency splitting, resulting in system performance deterioration. This paper presents a solution based on reactive resonant shielding to effectively attenuate the undesired cross-couplings, allowing the mEHC system to be more compact. Finite element analysis (FEA) and benchtop experiments have been carried out to verify the proposed shielding design in a prototype including two EnerCage-HC systems. The measurement results show that the proposed design reduces the cross-couplings by 94.4% compared to the case without shielding. This electromagnetic isolation between adjacent EnerCage-HC systems enables compact arrangements without performance degradation.