If I understand correctly what you are trying to achieve, I am afraid it is not possible. You cannot "combine" (move, connect, etc.) the branches and/or outcomes. You cannot drag&drop the "lines" in the workflow builder.
Let me guess, you have a some kind of process diagram/picture in front of you, and you try to "replicate" it with the workflow builder? Most likely it will be impossible. You need to find the ways to achieve the same things with workflow. As Rick said, perhaps if you give us an example (and a screenshot), someone will guide you through the problem.
Regards,
Karri