Using Post title as link to external site

I am in the process of creating an online newroom using WordPress. In most cases I will not be utilizing text for the post.

Here is the general format:

date Entry title
date Entry title
…
etc.

In most cases I will only be using the title field, not text. I would like to be able to take the visitor to the external site/news release upon clicking the title of the entry.

I may also occasionally use the text field, not just the title field. In these cases, the link would be treated normally (take the user to the post).

In this possible? I looked at the possibility of somehow of using a custom field in the situations when I’m using the entry/post title with an external link. I’m unsure about how to go about this.