Relational field type with Eloquent Models

Hello, I'm currently working on statamic v3 with the flat file storage driver on an existing Laravel app. My Laravel app has an other Back Office where I can create some records through the Eloquent ORM (Records are stored in the Database). I would add a select field on a Statamic Blueprint where I can choose between these Eloquent based records. I saw that an Eloquent driver already exists for entries, but I don't want my Eloquent Model become Collection/Entries in Statamic, and I want to stay with flat files in statamic. Have someone already experienced this usecase ? Is there a way to create a custom Field Type to make this working ? Thanks