Hi,

From what I understand, you don't need to use a "Path expression", but simply a more complex Target Finder Expression than just a plain reference access. Path Expressions are used to highlight series of individual edges that constitute a logical path (see for example the path in blue on https://imgur.com/a/8iIrN).

A Target Finder Expression can be an arbitrary complex navigation expression inside your model, typically written in AQL and/or in Java. If you're not familiar with AQL, the simplest is probably to write a Java services (it's just a plain Java method that needs to follow some conventions):

public Set<WebService> findWebServicesForClient(Client client) {
   // Use plain Java to navigate inside your model using the normal EMF APIs and build the result.
}

and then in the VSM, the Target Finder Expression simply needs to invoke the service (make sure its class is probably registered): service:findWebServicesForClient