How are people checking LAN availability out of Miami on BA? For example, if I go to the BA site and try to book MIA-MDZ for example, it will show the MIA-SCL portion as being in AA and SCL-MDZ on LAN which drives the points way up.

Is there a way to make it use only LAN when searching?

Also, checking Expedia LAN flies out of SJO Costa Rica to SCL, Lan Flight 601. But when I try to put in SJO on the BA site it says their partners don't fly there. Is this because this flight is operated by LINEAS AEREAS?