How to dynamically populate field with list of forms completed by a user?

I know this has to already be answered somewhere in the forum, but I haven't been able to find it. I'm a new GF user and would like to have two forms that sort of play off each other like this:

Form 1 - Collects information like you'd see for a real estate listing ... The post title is the street address. It's in the Post Title field of a Custom Post Type called "properties" ... It's also in a category called "properties".

Form 2 - I'd like to be able to use the second form to add more information from time to time that might relate to any property in Form 1 ... For instance, Form 2 might only need one date field plus a start and end time that could be used for an open house. This will be in a Custom Post Type called "events" and will also be assigned to an "events" category.

I want to keep these things separate so an agent can create several different open house events and just associate the info with properties created using the first form. This way, they could use the same schedule for multiple properties or they could schedule several separate events for a single property. I can easily give others access to edit only event schedules this way. It also makes it easy for me to filter events a number of ways.

To keep it simple for the agent, I'd like Form 2 (the event form) to have a dropdown list that is pre-populated with addresses of all properties created under the agent's login. (So, both posts would be created using the same login.)

How do I pre-populate a dropdown on Form 2 with the Post Title from Form 1? The user id and login will be the same for both forms. If needed, I can add any number of hidden fields, etc.
Thanks for any suggestions!

Carl,

Thanks for the reply and the link ... I feel like a total idiot, so please bear with me. I'm struggling less with the php portion than I am with what to do in the GF interface. Since your reply popped in 4 hours ago, I've read over the walk-through a dozen times ... I've read every other post on the subject that I can find. I am, thoroughly confused at this point.

I think all I need to know is: Based on the walk-through you linked me to, which information goes where on the GF dropdown item? Am I to use a simple dropdown? Should it be, maybe the category dropdown (I think not) from the Post Fields?

Again, sorry for being dense ... I'm amazed at the level of documentation you guys have ... I've just been struggling for a more basic understanding of which variable goes where ... AND the syntax to use. Punctuation of any sort?

Again thanks for any help you can offer!