double residency (Hong Kong)

Hi everyone,
I was wondering if it is possible to have a residency in another country than HK while having residency in HK. Does anyone know? My friend who is a resident in HK would like to join my business in Switzerland, but the Swiss government requires to have residency in Switzerland. Is it true that HK doesn't allow double residency????? And what will happen with the tax. Does my friend have to pay tax in Switzerland and HK for the business that she will have in Switzerland and also for her earnings in HK???
Are there any good websites to find out more info on taxation and resident laws in HK? Thanks