Help with dynamic block (stretch, array , move) in one

[franco.l452343]

I have this dynamic block for canopy decking. it will array out from both directions and has one of the bottoms pcs that will change from 6" to 4.5" and adjust the assembly accordingly. I would like to have the option to change any one of the bottoms pcs to 6" or 4.5" and have the assembly adjusted but can quite figure it out. The file is attached  Any help would be appreciated 

[j.palmeL29YX]

I think you must draw a second version of your complete geometry, but based on the 4.5" part, add the same parameters and actions as you have in the well working 6" version (of course with the appropriate values). Then switch between both versions using two visibility states. 

[franco.l452343]

Thanks for the response. I think I understand what your saying but I'm not sure 

My current process:

So I bring this block in and array it across the beam the decking sits on top of and if the decking does not end in a desirable spot overhanging the beam I adjust one or two of the 6" bottoms with a 4.5", so I only need to select one or two pieces to turn into 4.5" and the rest remain the same. I have tried visibility states in the past but found a hiccup in getting the remaining assembly to adjust 1.5" difference when a piece is changed to 4.5"

If I am repeating myself here I apologize but just to clarify what I am trying to make:

What I am trying to create is the basic 6" assembly that arrays but also has the ability to select any one of the 6" bottoms in the array-adjust it to 4.5" and have the assembly move over 1.5" to meet the new 4.5" bottom. Every piece needs the ability because the adjustment never happens in the same spot.

[Libbya]

You cannot adjust individual items in an array.  If you did, then it would no longer be an array.

[j.palmeL29YX]

If this is what you want to get

that can't be done with a dynamic block. I'm afraid you must explode the block reference and stretch the model manually as shown above. 

If the shown result doesn't meet your goal show us an example how the model should look after changing the width to the new value 4-1/2.