Finding total received power using HFSS

I'm using HFSS to simulate an antenna setup where I have two transmit antennae placed near a receiving antenna. All antennae operate in the same frequency. I'm interested in how the fields interfere with each other (constructive/destructive) and the resultant power in the receive antenna. The problem is, the S-parameters will give me the ratio of powers for individual transmit-receive pairs, but I need the resultant power from the superposition of fields originating from two sources. How would I go about getting that? I am a novice at using HFSS, so I would highly appreciate any guidance in this matter. (I use half wave dipole antenna and a radiating boundary.)