Q:

Split up routes in same router with reach-router

Say I have a lot of routes and I would like to split them up in groups.
How would I accomplish this in React with Reach Router?
Example of what I'm basically trying to accomplish:
const Router = () => {
    return (
        <Router>
            <AnonymousRoutes />
            <SecureRoutes />
        </Router>
    );
};

const AnonymousRoutes = () => {
    return (
        <>
            <Page1 path="1" />
            <Page2 path="2" />
        </>
    );
};

const SecureRoutes = () => {
    return (
        <>
            <Page3 path="3" />
            <Page4 path="4" />
        </>
    );
};

A:

Edit: So, I based my answer off of a misreading of your problem statement. I thought I read react-router, not reach router. I apologize. 
So using a fragment is exactly what you probably SHOULD be doing. However, React Reach doesn't currently support fragments. Silver lining, it looks like it will soon! 
https://github.com/reach/router/pull/289
If I'm understanding your question correctly, I think what you're looking for is  Switch from react-router.
The switch component allows a developer to segment out their routes and render specific content on the path. 
It might look something like this:
import { Switch, Route } from 'react-router'

<Switch>
  <Route exact path="/" component={Home}/>
  <Route path="/about" component={About}/>
  <Route path="/:user" component={User}/>
  <Route component={NoMatch}/>
</Switch>

