Turbotax can not handle this with just 1 k-1. This may be important because SSTB QBI is subject to special rules.
what I suggest is using two k-1s for the same entity. hopefully box 1 and the sum of the 2 reported QBI income are the same. then the non-SSTB portion of box 1 would be entered on the first k-1 and the SSTB income portion of box 1 would go on the second.