Must I abandon my project now? Is it possible to patent a website as a whole or a combination of features for a specific target group?

A website as a whole (exclusive of the generic concept of a website on the WW Web) is not an invention and therefore cannot be patented as such. An invention is limited to a Process, Machine, Manufacture, or Composition of Matter. A business method might be patentable, depending on a number of factors. There is no such thing as a worldwide patent, although it is possible to reserve rights to apply for a patent in a large number of jurisdictions (i.e. PCT aka patent cooperation treaty). If you feel sure your combination has substantial value that should cover the expense of investigation and/or applying for a patent, then you should engage a patent attorney to decode this situation for you and help you decide whether your method is patentable and makes economic sense.