Hi Raf,
The filter rule that you are expecting should be easy to build logic into he java script for the approval rule (filter rule) so that only the ultimate approval node remains on the approval flow.
Having said that I don't believe its a best practice to surpass the approval hierarchy as it will take out the denial capability of immediate supervisor(s) and a routine purchase would be a news to the intermediate people who get filtered out on receipt of the item.
Cheers!!
Vilas