Yes if the default settings/capabilities are not enough for you, you can always extend the functionallity with the SDK. But the first step should always be to try it with the default OneAgent capabilities.
Oneagent SDK does not have such feature at the moment. Maybe @Jakub M. will share if is this on the roadmap. Currently you can use Oneagent SDK for sending metrics just for process groups and hosts and do alerting on those metrics.