I tried this and it worked.
Create a multiframe with as many frames as you have SWFs. Make sure you have an HTML page for each SWF.
In the HTML page for each SWF put this in the BODY tag. Make sure your width and height match what your SWF's width and height are. This should eliminate any scrollbars from the browser object.
Code:
<body style="width:656px;height:600px;border-style:none; overflow:hidden;position:absolute;margin-left:0;margin-top:0;margin-bottom:0;margin-right:0;background-color:transparent;text-align:left;left:0;top:0;">
Now let's say you have two SWFs. Each multiframe has a browser object sized to the size of the SWF and set to display the HTML page for that SWF. For the second frame of the multiframe, make sure browser object is set to hidden. Then create buttons to navigate through the multiframe. I had to move the HTML and SWF files over to the publication directory myself after I published, but then everything worked as it should. I don't know how it would work if you had giant SWF file sizes, because I would think Opus would want to load them all, but this did work as you wanted.
Hope this helps or perhaps gives you some other thoughts.