If there is, I too would love to know how to make it work. As far as I'm aware of the only way to hide or show dialog buttons is to interact with a "clickie" object.
I had to modify my dialogs and have the player move from one console to the next to gather the clues and quite honestly, that's not very elegant.
It's not hard to come up with excuses to have players run around a map to interact with consoles and objects, but it would be so much easier to work with, modify later on, and a lot more simple for player to gather all their information from one place (when it's logical of course), than having them do the run-around game.
Anyhow, if someone finds a solution for this, I would welcome it with open arms.
PS: Thinking about what you said about buttons not being an object (that isn't quoted). A condition could be added like a prompt is, but called condition, where you could toggle it, or make it a certain number, after a certain part of a dialog. Like, you've asked the guy's name (add one), asked his assistant's name (add one). In the button you want to add to the dialog you check if the condition is true (2 in this case), then make the dialog option visible.
The story dialog objectives are very limited. Though you could use one console if each dialog was triggered after each other, but interacting with the same console again. This however is a nightmare of repetition in your story stream. My suggestion is using map triggers instead of the story stream to get some of your interactions and dialog in there. There is an awesome series on triggers, and using dialog with them. Just google search STO foundry Triggers and it should bring it up. It has about 5 or six parts I believe. Good Luck...
@de-noir: I have watched several times pretty much every video pertaining to the foundry, most are pretty good and informative.
I understand what you're saying and I do know how to set it up, but this feel unnatural to me and the story flow. I almost used "realist" but we're talking about a game here. Nonetheless, I will have to revert to a similar stratagem to fix the Foundry's shortcomings.
Let's look at it this way: If you have a contact that has done his research, why send the player on a clue search when that person should be able to inform the player ? I can't understand why this wasn't integrated in the foundry in the first place. Then again, maybe it's planned...
Currently, dialog response buttons have states and respond to triggers that determine whether or not the dialog response button appears or not. However, dialog trees themselves can either be completed (success) or reset (failure) and thus there is no way for individual dialog response buttons to communicate (and affect) one-another.
This means that currently the only way to create the functionality described in the original post, you'd have to create an entire dialog-tree with multiple repeating parts that eliminate dialog response buttons as the player progresses through the dialog tree.
This could change with the next Foundry patch, or remain in effect for the foreseeable future.