Well, there is some other workaround for you:
But I'd named it as "anti-pattern": it's breaks the main purpose of message-flow. I don't like any transformation of the payload in the interceptors.
<channel-interceptor pattern="routing1, routing1, routingN">
I'd said you need: Routing Slip, but unfortunaly we don't have yet similar solution in the Spring Integration: https://jira.springsource.org/browse/INT-267.
So, you can vote it and may we pull this issue to the closer timeline.