Here's one option - don't know if there's more.
In your tables tab, set up all five tables (4@8, Final @ 10). Once all five are set up, right click on seat 1, and select "make unavailable". This will bring up a dialogue where you can type in what you want - "Reserved for finalists", for example. Repeat so that all ten are set up that way. Then, click on collapse order, and move "Final Table" in the column of "Collapse these tables last." Alternatively, if you have tables set for collapsing first, you could move Final Table to the bottom of that list, and ensure that the box for "in this order" is checked.
Again, I don't know if there are other options, but this would at least take care of what you're looking to do.