Hi Shake,
You'll need to modify source to get the display effects that you want.
The good news is that Exhibit and Timeline are open source, so you
can. Look at how original-painter and detailed-painter paint an
event's icon and tape. You could paint multiple icons per tape. Also
look at how non-precise event tapes are painted one above the other.
You could paint small "tick" marks to indicate the multiple dates
during the overall events.
If you want your changes to be further enhanced and maintained,
contribute them as additions to the SIMILE widgets. (Make them open
source.)
As corporate IT projects go, sounds like fun.
Good luck,
Larry