I'm curious as to this as well. Also, curious of 2 other points:

can you fly [int'l city X] - Riyadh [then drive or fly domestically to Jeddah or another domestic city] - fly to [Int'l city Y]? Or is it that your 4 days must be in the same region of your flight?

Separately, can you do a stopover in Riyadh one way, and another in Jeddah on the return?