How to block on direct route

[Dennis Holunder]

Hello,

What is the correct way to block on a "direct" route until completion?
In the route below I must ensure only one instance of "direct:process"
route running. In other words, "direct:process" must not run in
parallel, because of some state

        from("timer://first?period=1000")
                .to("direct:process");
        from("timer://second?period=5000")
                .to("direct:process");
        from("direct:process")
                .log("processing");

Thanks!