Let's say you have Inflow A and Inflow B as well as Outflow A and Outflow B.  When Inflow A starts the task, it should then travel down Outflow A and vice versa.

You can set it up so that Inflow A goes to the task with outflow A being the only outflow path.  Then take inflow B and connect it to the copy of the task and make the only outflow path Outflow B.  This will make it so that whatever inflow was taken, the corresponding outflow path will be taken as well.