You might want to contact Support for this issue (link below), but it does not appear as if you can generate only one K-1 given this scenario. You will either need to generate two K-1s or print the return, make the adjustments manually, and the mail the return.
https://ttlc.intuit.com/community/using-turbotax/help/what-is-the-turbotax-phone-number/00/25632
