Array Termination in Dynamic Block

[MaxwellEdison]

I'm wondering if anyone might have any ideas on what I'm trying to do in this particular dynamic block (attached below). Basically this is part of a set of dynamic blocks which will allow our department to put together details of typical connections in a modular format. This particular block is the work in progress for a porch. What I'm attempting to do is array the deck boards as the porch is stretched. Our porches are typically (but not always, never that simple) 72" from the outside face of the post to the edge of the deck board (which is ripped to fit). The array is working fine, but I can't come up with a way in which to terminate the arrayed object.

 

This block is still a work in progress so I haven't assigned the visibility states yet, all are on. There are 2 types of decking overlayed on each other, typical 2x6's and 7/8" thick compisite. Also the break line shown will be replaced by a vertical line, however its behavior really shouldn't matter. I've attempted wipeouts in the past but this hassn't worked as the arrayed objects are always drawn over any existing objects. Anyone stumbled into any solutions for problems such as this? Or have my desires outpaced my abilities?

PorchSample.dwg

[MaxwellEdison]

Upon rereading my post, I think a little clarification is in order. The main problem stems from the action Array1 which is tied to Stretch1. I think you will understand better if you change the Porch Length under properties to be 72". I need a way to terminate the last deck board at the cut line while still preserving the ability to lengthen or shorten the overall porch length. Again, any help or insight is appreciated.