Press MC's down

What I am trying to do is to force MC’s to press each other down after loading content.
I have MC1, MC2, MC3… Each MC has dynamic text box with function “content_txt.autoSize = true;” and each one is loading text content from XML files.
Is there any way to force MC2 to go down, under MC1, depending of the size of loaded text in MC1? Something like: MC2._y = MC1.height + someNumberOfPixels