Way back in the day -- early or mid-1990s -- I had 1.2 parsons. My male was introduced a couple times to other males and would not tolerate their presence. My females were sometimes free range, but kept their distance from each other. Whenever my females got close to each other, there was lots of tension between them.
Your males in the image seem to be a yellow lip and a standard orange eye. Could this difference contribute to their toleration of each other?