By theory, you need not to pay commission to Agent A. But in reality is that---Agent A did the effort to show you the property E. Agent A might not be happy that 'Done the job and have no pay'. ... Agent A would know you and your family have bought the property as it would be publicly listed on government Land Office !
many things would be happened......especially anything that concerning with money...........many many thing might be happened! You got the meaning?