I do'nt know if i should start here, or if i am in the right place, but since it involves a NW(DL) flight, I thought I'd ask here.

I am trying to price out a fare ex. MSP-IST via ORD with NW/TK

Pricing this seperately NW MSP-ORD r/t is $194.20 and then TK ORD-IST r/t is $649.15, however when I try to do multi-city pricing on expedia or the likes, trying to combine these flights, these options arent there, the only options then showing are UA/TK or AA/TK or NW/KL and the cheapest price is then $1007.40 or something.

The two individual tickets price out to $843.35, which is much more reasonable to me. I want to try to get these on one PNR, anybody know how?

I am just curious that if I hold a NW MSP-ORD and then a TK ORD-IST ticket, when i try to check my bags at MSP interline to IST via ORD, I dont want to end up with NW trying to charge me for baggage, since i'f flying international.

I wonder if i try to hold a NW res on their site and then go back and call nw and see if they can add a TK section to the res, but i Doubt it is possible. Anybody know how to go about this?