Adding Exporter to Prometheus (Istio)

Hi, we are trying to add some exporters (using annotations) to the prometheus install as part of Istio. But have noticed the ‘prometheus.io/scrape’ only looks at the ingress-nginx, ingress-controller, and kube-system namespaces. Is it ok to add to that list - if yes, what is the preferred mechanism. Otherwise, should we install another Prometheus for our monitoring? Obviously we’d prefer to just use the instance in Istio…. Just looking for recommendations.