Custom Fields & Blueprints

I am currently using custom fields to track social media posts in a content calendar.  I am using custom fields so that we can specify the social media platform (with a single-select custom field), dates, and other metrics with custom fields.  However, when I go to edit my blueprint for this project the newly created custom fields are not available.  I don't want these custom fields to show up in all of my other projects so it would be great if we could have a full list of ALL custom fields in the blueprints so that no matter what project you are creating or editing the blueprint for, the custom field that you created for a specific project can still be available for the blueprint.