Throughchecking to final destination with separate IB tickets doesn't work. The last time I tried to do it, I was told that the system doesn't permit it (more likely employees don't know how to do it) and I'm not the only one in FT with similar experience. If you have to get your luggage from the belt, two hour connection is very risky as IB baggage handling at MAD is very slow. Quite often priority bags arrive 40 minutes after arrival at MAD...