Recommended action

You can remove the inner loop in the ConnectedVia relationship and treat the return value of pObj->ConnectedVia as an object handle.

foreach probe (getInstances("Probe")) {
    pObj = object("Probe", probe);
    foreach ipNet (pObj->ConnectedVia) {
// This returns all of the objects in the ConnectedVia relationshipset
        if (ipNet->CreationClassName == "IPNetwork") {
            print(probe . " is ConnectedVia ".ipNet);
        }
    }
}