Make iTunes choose library every time it opens?

I'm familiar with the option key method to have iTunes let you choose between different libraries when it opens, but I want to find out if there is any way to force iTunes to always ask this every time it opens. I have two, one that is connected to my external drive and the other is strictly music on my macbook. The problem is that I forget sometimes to close iTunes when leaving home or work, or I forget to hold down option when I open it.

I've looked everywhere in preferences with no luck and searched the forums but apparently I'm the only person that wants to do this.

Can anybody suggest a method that could automatically include the option key function when iTunes opens every time?

Thanks!