One thing to remember about Apogee Impose is that bleed has no control over the space between elements. It is only a setting that will allow an image to extend beyond the final trim size provided there is a margin (trim).
If you are not yet running Prepress 7.1 acomplishing what you want is a little tricky. What you need to do is set your job with 10 parts instead of 1. Then you can adjust the margin on each individual card. You can leave the bleed to 1/8 on all the cards and just alter the margin. For example the card, say 1, in the bottom left corner of the sheet would have a left side and bottom margin of 1/8 and a top and right side of 1/32. The card next to it, say 2, would have a bottom of 1/8 and a top, left and right of 1/32. When you populate the run list you drag the same page in to all 10 positions.
If you are at 7.1 this is much easier. In the press sheet view position the cursor in the gap between two elements then click and hold. You'll see red ballons show up. Select the one that says vertical or horizontal gap. Now you can adjust the gap either between the margins or page trims. You'll want to select page trim and set it to 1/16. Repeat this for all the gaps on the sheet.
-Phil Crosby, Senior Trainer, Academy, Expert Services, Agfa Graphics North America