array constraints?

[jessica.146534]

I'm trying to add horizontal lines to the elevations of an overhead door family. I used the array command and added a parameter to the # of lines so I can change it for varying door heights. The problem is that I can't get the lines to lock to anything so they will stretch as the width changes. I tried drawing the first line and locking it to the reference planes, but the array seems to lose the locks. And then I tried locking a line in the "edit group" command but I get an error message that says:

"Changes to groups are allowed only in group edit mode. Use the Edit Group command to change to all instances of a group type. You may use the "Ungroup" option to proceed with this change by ungrouping the changed group instances."

Any ideas on how I can lock the lines to the reference planes so they will stretch?
I've attached my family for reference. Thanks in advance for your help!

[cdatechguy]

To make things easier with array's I create them as a separate family.....that way all I have to do is align and lock the origin reference planes of the embedded family and link the width and height to the primary family...Even if your just using lines...;)

[jessica.146534]

aha! I knew I had done that before. Thanks for reminding me about nested families!