Imagine you want to buy a round ticket from A to C. You have one stop in B (all three cities are in different countries).
A -> [B] -> C -> [B] -> A
B is actually an interesting place and now that you have to land on it you may like to stay there for like some days so you can visit B without buying extra tickets. The problem is that I cannot choose the dates of my flights to and from B and the booking system selects them without my control. If I do so it will not be considered a round-trip and the cost of a multi-city booking is like buying three or four one-way tickets that are way more expensive than my round-trip with one stop.
If I try the multi-city option on Google Flights, to buy tickets from A to B, B to C and C to A, I have to pay for three one-way tickets! and the overall cost is way more expensive than buying a round ticket from A to C! (it's even more expensive than the total cost of two round travels (AC+BC).
Are there any solutions?