Is there a way to book a round-trip multi-hop flight when not all classes are available in each hop? For example, if you try to book a flight from BWI to DAC, in F, the BWI-JFK segment only has Y and the DXB-DAC segment has Y and J. However due to the BWI-JFK segment only having Y, you can only reserve a Y flight all the way through (even though JFK-DXB is the A380)

I did notice that if I split it up into multi-city (basically six flights), you could specify the class, but this seems excessive - is that the only way?