Embedding multiple interpreters

I would like to allow users to write Julia-based plugins for my software, which is written in a C-like language. I had a look at the embedding manual which seems really straightforward. However, I don’t know what the right approach would be if I wanted to support multiple execution contexts. If the user loads multiple plugins, written in Julia, which would each make and receive function calls to/from the C application, how would one allow the code of those plugins to not interfere with each other? Can you load/store the state of the interpreter to allow multiple independent Julia programs to be embedded in a C application? Or would you use separate OS processes, like how web browsers do it with Javascript?