not allow user to create records in layout

[Archit3kt]

Is it possible to change the permissions to disallow the user from creating a record in a particular layout? I don't want the user to be able to create a record that isn't immediately linked with a record in my second table, so I have a portal in the second table's "detail view" layout where they can add a related record.....but I want to have a "detail view" layout of the first table that shows more fields, but won't allow record creation.

I have a table of companies, and a table of contacts that's linked via an ID# field. The user can add a contact from a portal in a company's record in the layout "company detail view", but I DON'T want the user to be able to add a record from the contact detail view, because it will not be linked with any company.