How to correctly change data in a model with redux forms?

Question

React

Good afternoon!
Please tell me how to solve the following problem correctly (using react, redux, redux-forms). I have a LocalForm with fields that have the model attribute. When submitting a form, all model data is sent to the server, but there is a need to send data stored in custom components, whose source code cannot be edited. Is it possible to somehow add data manually to the model sent to the server, or create a hidden field with the model attribute and put data into it?