Just trying the answer this myself and found that the MIA website is useless in this regard. All it shows is primary colors for the 3 terminals south central and north with no indication of what is inside security. Im flying MIA-IAH today on UA out of G. I already know D-E are inside security with no access to the other terminals but is G totally shut off from the other airsides. IT seems to be pretty dumpy without any lounges of any kind.