THIS week, the great and the good - or, at least, Beijing's version - will gather in the Chinese capital for two more key meetings of sub-groups of the shadowy body that is supposedly entrusted with the task of ensuring a smooth transition for the territory. More than three months after its creation, the Preliminary Working Committee for the Preparatory Committee of the Special Administrative Region, to use its full and unwieldy title, remains a largely unknown quantity, a problem yesterday's opening of a luxurious communications office in Central is unlikely to do much to diminish. Better known as the PWC, its meetings are closed, its members forbidden to disclose what takes place in the rooms of the Hong Kong and Macau Centre in Beijing. The only illumination comes at the end of session briefings, when panel chairmen are meant to enlarge on what has transpired, but all too often only succeed in adding to the confusion. Certainly that is what happened after the recent legal sub-group meeting, when Hong Kong co-convener and former Appeal Court judge Simon Li Fook-sean was widely interpreted as warning the Bill of Rights might be repealed after 1997, only to subsequently deny saying anything of the sort, while his mainland counterpart, Shao Tianren, adopted a more cautious attitude throughout. There have also been other embarrassments as ambitious members of the PWC - which includes virtually all leading contenders for the Chief Executive after 1997 - gently jockey for position by making increasingly outrageous suggestions. Businessman Vincent Lo Hong-sui has repeatedly insisted Financial Secretary Hamish Macleod should consult the PWC's economic sub-group over financial policies, even as he denied harbouring any ambition to become Hong Kong's first post-colonial ruler. Another potential Chief Executive contender went one further and tried to suggest Standard Chartered and the Hong Kong Bank be banned from issuing banknotes after 1997, an idea China's top official on Hong Kong affairs, Lu Ping, had to swiftly squash, pointing out it would violate explicit provisions in the Basic Law. There has also been internal bickering. Maverick lawyer Liu Yiu-chu has so far refused to attend any PWC meetings, due to a bizarre feud over the precise status of the body, and whether its members are accorded too high a status, relative to National People's Congress delegates, of which she is one. Former Executive and Legislative Councillor Lo Tak-shing has also been busy sniping at the PWC political sub-group, which he was reluctantly persuaded to give up his seat on. Mr Lo has repeatedly suggested - through his magazine Window - that this group will have little to do in ''unpolitical'' Hong Kong, while the real power will rest with the legal sub-group, of which he is a member. But the problem for the PWC is that its precise role remains unclear, and is likely to remain so, at least until the outcome of the talks over electoral arrangements for the 1994-95 polls. Although officially only an advisory think-tank with no power to do anything other than make recommendations, the PWC was originally expected to adopt a more powerful role as a ''second stove'' or shadow government, that would be able to virtually veto all the Hong Kong administration's decisions during the final years of the transition. Such a scenario was made to seem more likely by the appointment of Vice-Premier and Foreign Minister Qian Qichen as PWC chairman, a much more senior figure than those originally mooted for the post. Yet that has so far showed no signs of being likely to happen. Instead the new body is clearly being kept in reserve, as a weapon to be used if and when the talks break down. Indeed, the next full meeting of the PWC - as opposed to this week's sub-group sessions - is not scheduled until December, by which time the fate of the political reform negotiations should be known. If the talks do break down, the PWC is almost certain to assume an enhanced role. Its membership is likely to be enlarged, perhaps bringing in the likes of Liberal Party leader Allen Lee Peng-fei, to boost China's united front strategy and counter criticisms of the narrow nature of its original membership. The PWC's remit will also expand, to include preparing to reconstitute Hong Kong's ''Legislative Council, Government and judicial organisations'' - to quote Mr Lu's original announcement of the ''second stove'' a year ago - from scratch in 1997. The bodyis sure to emerge from the shadows and attract more public attention. But if the talks succeed, however unlikely that may seem, then the new body is destined for the more minor role of simply rubber-stamping whatever British and Chinese negotiators decide. It might even find the only decisions where the PWC can exercise any influence are trivial matters, such as designing new stamps for use after 1997, or organising the firework displays to mark the transfer of sovereignty. Just as the title of Hong Kong Affairs Adviser to Beijing, that was thought to be so valuable when first introduced early last year, has come to mean little, since so many people have been given the title, membership of the PWC could equally come to be seen as irrelevant. That depends on factors outside its members' control. So, as they gather in Beijing over the next few days, all the PWC appointees can be sure of is that - like Hong Kong people as a whole - their fate is not in their hands.