You can achieve this by describing the situation and letting people think about what they will do.
I mean, you already do it all the time, right? You just say
The flag of Dobravia flutters in the evening breeze, two crossed swords in a field of blue.
Even though Grognak is standing right there! Grognak, who was raised by wolves in the frozen Northern Lands and has finally mastered "two" but has no concept of swords, flags or the blue color. (He calls him "pale black.")
You are not describing what any particular character is seeing. You are describing what "the camera" is seeing, in terms that the players will understand, and letting them decide what their characters take away from them. You are describing the situation.
In the same way, you can say
The bustling market surrounds the town square. There is a fisherman, a sausage shop, half a dozen wardrobes in a variety of styles and, deeper than you can see, you hear someone hammering the anvil with force and speed.
Do not ask who looks to the left and do not talk about the sausage shop (which is on the left) if there is no one looking there. Their the market situation, and your players decide what is important to them.
So sure, describe the situation of your agenda, which will include not only what they would have to do but also the reason why they would have to do it.
Grognak, the last time you faced [Group X] they licked their wounds and told you to come to Dobravia if you wanted a real fight. Well, here you are.
Wizzrobe, the portents of [Bad Thing Z] It still burns in the Crystal of Glimmorath. According to the directory of the Academy, [Knowledgeable Guy Y] He has established a store somewhere around here. So, how to find a wise man?
Companion of strings, everything you achieved [FindThisGuy A]The trail is that it was heading north. And this is the north, and the only patch of civilization you've seen in miles. Maybe it's worth asking around, see if anyone has seen it. You know, in the lower part.
So! What is everyone planning?
The horrible price to pay
Of course there is one. Nothing is free.
The price to pay is that, like GM, you know more about the world than you have told the players. It is inevitable. Therefore, you must take action on your part to keep notes on what the players know, separately from their own notes. Maybe you can mark your own notes in a different color, as long as you have a clear understanding of what it means.
Otherwise, you risk ending up saying something like
The flag of Dobravia flutters in the breeze of the night, a blinking illusion that hides the banner of Ossian, the King of the Dead, who secretly became too strong, wait, wait, you've never heard that!