Flash interactivity with button over background

For an ongoing project i have to implement a Flash-"Welcome" screen similar to this.

I know how to create these two buttons (left and right with the two hotels on them) but i don't know how to make this smooth transition when hoovering over a hotel from one state (mouse not over button) to the other (mouse over state) WITHOUT affecting the background (clouds).

Is this "transition" made with or without Actionscript? (always bear in mind that the clouds have to hover in a straight sequence - the开发者_Go百科y can't be "rewinded").

I'm new to this tech so i' don't have the feeling of how exactly this has been constructed, i think i miss a lot.

Thanks in advance

PS. Flash CS4 is used

You need to construct your FLA is such a way that the clouds are in a different MovieClip than the two buttons.

In the example you posted, they most likely have one (background) MovieClip with the sky, water, hotels, and clouds. When the SWF starts it plays that MovieClip, which is the initial animation where they make it appear you are skimming the water toward the two hotels. Once that plays in, they are triggering the two buttons which are in separate MovieClips sitting on top of the background MovieClip. When you mouse over either of the buttons only the button is changing state, not the background. The background just keeps playing.

Make sense?

EDIT

Here is a really basic example. http://www.gigasize.com/get.php?d=mhfkqw59mwd Note: this was done very quickly just to illustrate the idea.