Chris:
I just realized, are you trying to counter-sink the drivers?
If so, the job will be much more difficult. You have really only two options in that case: get a router and get a skilled craftsman to teach you how to use it, OR drill the outer hole to a specified depth using your drill press, and remove the in-between material with hand tools (chisel, brass hammer, files, sandpaper...)
The second way above is much more labour intensive and will not yield as good a result as doing the counter-sinking with a router, but it will be cheaper in terms of tools, and is really the only recommended way (by me) to go if you don't have someone to teach you how to use the router properly. Designing a jig, doing the cuts, blah blah, is NOT something you'll get right (well, before the 10th try) by yourself.
I suppose a third option exists for counter-sinking the drivers, see if you have a friend with a CNC (computerized) milling machine. Then it's all software.
Wes