Using MB custom fields to create CPT title

Hi -

I have a CPT for Employees. I want the title for each post to be the Employee First + Last Name.

I have custom fields for First Name and Last Name.

How do I name the post using the First Name + Last Name instead of the default post title field?

Example:

Employee name = John Smith. I need the post title to be ../employee/john-smith/

Any suggestions?