Virtuemart Customisation

We need a Virtuemart Customisation for different countries and currencies. We sell products in switzerland in CHF and the same Products in Germany (or EU) in Euro. What we need is the usage of the shopper groups or any other solution to show the prices in CHF for a swiss customer and the prices in EURO for a EU or german Customer. Prices should be shown without registration (IP Geotag). There can be a selector on the page to show prices in Euro or in CHF as well. We do not want to do this with the currency selector, because the prices are not always the same and we want to have our own prices for eacht product. we were able to show both prices at the same time with a small hack ([login to view URL]) but are not able that a customer can order in euro for germany. if we assign a new customer to the shopper group (for example germany) the prices are still in CHF. if a customer chooses Euro only german (or EU residants) can order (Address must be in germany). if a customer chooses Swiss Franc, only a swiss curstomer can order (Address must be in switzerland). i hope you understand what i mean. if you have more questions, please do not hesitate to contact me. thanks in advance