1) The most effective way to track and communicate with contacts on a Business Account would be to add separate constituent accounts for the contacts of the business.  The main contact for the business would have their name entered into the Salutation fields of the business account's primary persona type. Then you can link the individual constituent accounts to the business account using a relationship (ex: Employer/Employee). This method is also good if additional data needs to be tracked for the contacts such as donations, volunteer information or any data specific to the individual. 

Check out How To Copy A Business Address From An Employer's Account To An Employee's Account so you don't have to hand type the Business Account's address into the business persona type for each employee.

2) An alternative solution is to track each contact in a separate persona type within the Business Account.  Each persona type can have a different contact's name listed in the  salutation fields (Long Salutation, Short Salutation and Envelope Salutation). This solution will allow for tracking all of the names on the business's account without the need to create separate constituent accounts.

For example, you can create several new persona types called Additional Contact 1, Additional Contact 2, etc... and store the individual contact information in each persona type.  Depending on how many contacts the business had determines how many persona types you will need to create.  As you can see this can clutter up the persona page if a business were to have 15 contacts.

Be sure to review How To Add Additional Persona Types so you can use them on the Business Account.
How To Add An Additional Persona To An Account will walk you through using the persona type on an account.

Persona Types are primarily used for tracking multiple addresses for the account.  Using this method is a work around to avoid having to create multiple accounts for each contact.  So there could be some difficulty in query, reporting, or mailing depending on what information you need to pull.