Delivering growth in one area of a neighbourhood to prevent it elsewhere - Public forum - Planning Advisory Service (PAS)

I am working with a front-running neighbourhood planning group that is developing their plan in the absence of an up to date local plan or core strategy, and also without specific housing numbers for their area. They have seen a rash of developments that they deem to harm the sustainability of their area and have serious detrimental impacts upon parts of their neighbourhood. They have identified a couple of key sites that will likely satisy the vast majority, if not all of what will likely be their allocation when the housing numbers are published by the Borough Council. In return they would like to place a blanket prevention on development in specific other locations, either because of the impact on high character areas, impacts on specific roads with congestion issues, or to protect locally designated wildlife / green corridors. So far the advice they have been given is that they should specify in their policies that development in these other areas should not have an unacceptable impact on those aspects that are fundamentally important in the area. The group have concerns that this is too subjective and want to put a blanket ban on the develomopment of new homes for the period of their plan on specific locations (particularly in a relatively small radius of a village with a recognised congestion issue). Given that they will be providing adequate levels of growth in other parts of their neighbourhood, can anyone advise of any way that the group can achieve greater certainty against this inappropriate development in specific locations, that will withstand the examination and Inspectors at appeal?