Magnetoresistance and quantum Hall effect (QHE) are studied of hole gas confined in <$E p- {roman Ge} sub 1-x {roman Si} sub x "/" roman Ge "/" p- {roman Ge} sub 1-x {roman Si} sub x> quantum well (QW) within ranges of QW widths 8 - 38 nm and hole gas densities <$E (1~-~6)~cdot~10 sup 15~roman m sup -2> under magnetic fields up to 40 T and temperatures down to 0,1 K. Strong changes in the structure of QHE experimental traces are revealed when the upper subbands become populated and shown is that detailed information may be extracted from the analysis of these changes. It was found that in Ge layers wider than 35 nm hole gas is separated into two 2D sublayers located next to the interfaces. In this case the analysis of weak field magnetoresistivity yields relative characteristics of normal and inverted heterojunctions. At the intermediate stage of the self-organized formation of double QW, the quantized Hall insulator phase is discovered. For magnetic fields configured parallel to the layers, a strong negative magnetoresistance is found caused by depopulation of the upper subbands due to their diamagnetic shift in energy. Under parallel magnetic fields some additional peculiarities in magnetoresistivity of the samples with divided hole gas have been found, which are tentatively explained as being due to the complicated structure of energy dispersion surface of double QW formed in valence band.

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