Although there can be reasons for linking within a module, generally it is not a good idea. I guess you are thinking of a module as a document. Instead, think of it as a structured collection of information. If you do this, it is more natural to collect the high level requirements in one place (module) and the detailed requirements in another. (As an aside, that would generally be a better way to allocate them to documents as well).
DOORS NG doesn't restrict the types of links you can create between modules, but it does allow you to restrict the links you create between artifacts of different types. So you could have one type for high-level requirements and one for detailed requirements and restrict links to only go from detail to high-level. OK, you can still do this inside a module, so make use of the default artifact type settings for a type of module so that you have to consciously add artifacts that are not of the default types to a module.
You can do all this within one module, in practice you will find it is simply easier and cleaner to separate the levels. It is also easier to explain and understand if you ever need to draw the information architecture. Things that are easier to understand are more likely to be used properly.