There is a hacky way to do it with ModuleWrapper control. But this approach doesn't work well with many features. SiteModule is meant to be a base class for a CMS page plugin which requires publishing on a page to be able to correctly enforce page allowed roles and module allowed roles. It "may" work with your custom feature if your custom feature doesn't have supporting pages. Use it if you must, avoid it if you can.
See also
Hope that helps,
Joe