They will likely have areas of specialism, diabetes, asthma etc although they will all know a fair bit about all the general conditions it's only worth using the nurse route if you fall within their remit. Your practice should know who knows most about what. For example They all do wound care, but maybe only one will undertake extra courses above the standard tissue viability course and will be a resource for other nurses but they will in turn refer to a colleague who has greater knowledge if she has a really difficult asthma patient.