Yes. Planning Center exposes Groups through its API, and third-party tools use that to publish group content on your own website instead of leaving it on Church Center.
Planning Center itself doesn't offer this. Church Center is the destination they provide, it lives on a Planning Center domain, and there's no first-party option for hosting that content under your own address.
What the options actually give you
Widgets paste a script into a page and inject groups after it loads. The groups appear on your domain visually, but the HTML your server sends doesn't contain them and individual groups usually have no URL of their own.
Sync tools import groups into your site as real content. On WordPress that means a custom post type, so each group gets a permalink, an entry in your sitemap, and a page that exists before any JavaScript runs. PCO Bridge works this way, and also generates archives by group type, meeting day, and campus.
One thing stays put
Joining hands back to Church Center either way. Planning Center owns membership, so what moves to your domain is the browsing and the deciding, not the roster.
PCO Bridge is in beta and applications are open to churches, developers, and agencies.