Invoice Approval Workflow. Stages, Participants.

Summary

Trying to design workflow but unsure of best way to do it

Content

I am working on designing an approval workflow based on invoice source. Each source would then have a different approval flow based on other factors. Some flows would have 2 sequential approvals others 4.

I was looking at stages in hope that i could have a stage for each invoice source and within that stage define its rules for sequential approval. Each stage being parallel to each other such that when a invoice enters flow it finds the stage that applies to it.

I cannot find any documentation on how stages work or if they work like this.