Thank you for your post, and I apologize for the late reply. There were a few posts that were initially missed.
One option is to use a New Window script step. In FileMaker Pro, this opens a new window. With Instant Web Publishing, it creates a virtual window. That is, the same browser window is open, but the previous page is saved. Eventually, when you execute a script that uses Close Window, you are returned to where you were before the New Window command.
As a brief example, create two scripts, SECOND and ORIGINAL, with the following commands:
Go to Layout [ <another layout> ]
In your original layout, create a button and link it to the script "SECOND". In the other layout, create a button and link it to the script "ORIGINAL".
Go to your machine with a browser and open the file. Go to the original layout and click the button. It appears nothing has happened except switch to the second layout. Now, when you click the button on the second layout, you are automatically returned to the original layout, as if it said, "Go to Layout [original] "
Granted, this is a simplistic case, but this should get you pointed in the right direction.
Again, I apologize for the late response.