You can currently not use external solvers (OpenFOAM, FEniCS, SU2) together (at the same time) with the built-in multiphysics solver. However, you can use the solution from one solver as input to another, for example using the flow field computed by OpenFOAM with the built-in heat transfer physics mode as shown in the multi-simulation example:
https://featool.com/model-showcase/06_Multiphysics_09_multi_simulation1