Filter search of Experts based on custom field

I have created a custom field called "colors" for Experts custom post types in J&E. I'd like to use a function with an add_filter on jbp_expert_search_params to restrict the search results which are generated by /expert-archive/main.php. Specifically, I only want results to appear in search that have "colors"="red".

Can you provide a function to do so?

Thank you