  We present observations of the (1,1), (2,2), (4,4) and (5,5) inversion
transitions of para-ammonia (NH3) and 24 GHz continuum, taken with the
Australia Telescope Compact Array toward 21 southern Galactic hot molecular
cores traced by 6.7 GHz methanol maser emission. We detect NH3(1,1) emission
toward all 21 regions and 24 GHz continuum emission toward 12 of the regions,
including 6 with no reported 8 GHz continuum counterparts. In total, we find
the 21 regions contain 41 NH3(1,1) cores. We extract characteristic spectra for
every core at each of the NH3 transitions and present both integrated intensity
maps and channel maps for each region. The NH3(4,4)+(5,5) emission is always
unresolved and found at the maser position indicating that the methanol masers
are found at the warmest part of the core. We observe large asymmetries in the
NH3(1,1) hyperfine line profiles and conclude this is due to a number of dense,
small clumps within the beam. We derive properties of the ionised gas and find
the 24 GHz continuum sources not detected at 8 GHz are always coincident with
both NH3 and methanol masers in contrast to those detected at 8 + 24 GHz which
are generally offset from the methanol masers. We investigate the possibility
that the former may be hyper-compact HII regions. Finally, we separate the
cores into five groups, based on their association with NH3, methanol maser and
continuum emission. From the different physical properties of the cores in the
groups, we discuss the possibility that these groups may represent cores at
different evolutionary stages of the massive star formation process.
