Need help on hidden movieClips

Hi all,

This is the basic setup

hidden_mc is a symbol with opacity of 1%, which will rest on top of the 4 movieclips.
the grey parts are also opacity of 1% so that they look transparent.

hidden_mc._visible = false;
close_mc._alpha = return_mc._alpha = next_mc._alpha = 0;

During runtime, only next_mc is visible to the user. when user hovers over next_mc, close_mc+return_mc+prev_mc will appear via tweening using the Tween class, and hidden_mc._visible =true.

When hidden_mc.onRollOut,
hidden_mc._visible = false;
Tweening for close_mc+return_mc+next_mc from 100 _alpha to zero.

Works fine until this stage, but I am unable to click on the movieclips that I’ve assigned to all of the movieclips because hidden_mc is at the very front. I’m not sure if this is the cause that my MCs are not working.

Any experienced kind soul has a workaround for this?
Thank you.