I'm guessing this option is in plain view, available somewhere in the topic info>conditions>condition functions, but hopefully someone here can help.

I'd like to make a conditional NPC dialogue which becomes available only when the player has drawn the aggression (and/or is in the immediate aggro area) of a particular faction.

Example of this type: Say the player, or (immediate area) has drawn the aggression of a dragon which is currently circling in the air. If the player were to try to speak to their companion, a dialogue option would be present such as "Dragon!" which would/could be followed by responses/scripts etc.