Hello,
If you are using Topology #2 shown in Figure 66 of the datasheet you can connect 2 RTDs to the LMP90080. One RTD could connect to IB1m VIN0, VIN1, VIN6/REFP2, and VIN7/REFN2. The second RTD could connect to IB2, VIN2, VIN3, VREFP1, and VREFN1.
Mike