wdc, gpt or cer – which one ?

Hello all,

Assuming the general trading condition of the market is stabilising if I can (taken the behaviour of the market in the past few months). Comparing among sections, the property sector appeared lagging the overall market quite significantly.
If I would like to invest within the property sector, would i be buying (1) wdc (big), (2) gmg, gpt (middle) or (3) cer, vpg, hfa (small). Alternatively, should I just buy the XPJ index instead (would I be able to do that? Not sure at the moment).

Thank you in advance for your kind comments/thoughts.