Originally Posted by
irishguy28
I don't know if you tried to purchase all these flights in a single transaction - the only standard way to "link" travel on different airlines - it's not always possible to do so.
KLM certainly does publish ex-CMB tickets that interline with UL. Here are the routing rules for KLM's business class fares between CMB and SEA that include an interline with UL:
But obviously, these fares are probably quite a bit more expensive than the combination of tickets the OP purchased. One of the downsides of such a self connect is the hassle of hanging around self-connect airports.