Dear Shiela,
It is possible to design MCF in OptiSystem software. OptiSystem version 18.0 allows you to use analytical models for SM MCF designs. However, version 19.0 which coming in two weeks allows you design the structure of the MCF in OptiMode software then import the fields into OptiSystem and calculate the crosstalk. There is a recent paper (attached) that used this concept.
Regards,
Ahmad