Many to Many relationship

I was wondering if there is an easy way to create a many-to-many relationship in a backend form.
When i create a J_SQL field with multiple options, the different id's are stored in one single database field, but i would like to store this inside a many-to-many database table (other then the current table you are editing).

Is this possible inside CC or is the only way to change the save, get and delete functions inside the models?

Anyone?