It is technically possible to use arbitrary MATLAB functions with SimBiology. So you could in theory create a SimBiology model that calls source_terms to calculate the appropriate terms. But I would not recommend this approach. I think it would end up being very hard to read and extremely inefficient (that is, slow to simulate).
So, for all practical purposes, I would say you should not directly use source_terms with SimBiology. Instead, I would focus on finding an efficient way to convert source_terms into a SimBiology model.
Can you share your full code for source_terms? Depending on how that's written, I might be able to offer suggestions for writing a program to automatically create a SimBiology model from the file.