Select all MCs by dragging the mouse?

OK, suppose I’m creating a little app that has a bunch of toy railroad pieces (movie clips) that I can move with the mouse and connect to build a railroad.

I want to set it up so that, like Illustrator and Visio and other such apps, I can click and drag my mouse over all railroad pieces that I want to move together. I have set up my display objects so that they have an ‘active’ and an ‘inactive’ state, and any that are active will move along with the mouse. So, I click and drag to select, then I click again and drag to move all objects I selected.

Two questions:

[LIST]How do I code this such that all display objects that fall within the rectangle swept out by my mouse_down cursor become active?
[*]I would like to name the property of my movie clips ‘selected’ rather than ‘active’, but that’s one of those parameters that becomes blue when you type it. I’m not savvy on this – can i somehow override Flash’s use of ‘selected’ and use mine instead?