[1.15.2] Looking for a way to modify another mod's config files with my own mod

[lesternomo]

Title. To be specific I'm trying to, once the game stage is advanced (using the mod Game Stages), change the config file of the StructuresCompass mod to include new structures in the whitelist. If anyone could let me know if this is possible, and if so, how it would be greatly appreciated.  I'm new to modding so if this seems like it should be easy I'm sorry, I did a good bit of research and was unable to find anything that seemed to fit what I wanted to do.