split originations reporting

Until now, we have been pulling a simple report which shows the total fees billed or collected for a given period, sorted by originating attorney and those fees subtotaled by timekeeper.  However, we now have split origination situations wherein there is more than one attorney originating a matter.  So I have had to keep track and do the calculations manually to split the originations between the multiple attorneys.

Is there another report or method for which we can prepare a report that splits the originations between the multiple attorneys?  And still displays the fee breakdown by timekeeper.  So, if John and Bob want to split the originations on a matter and $20,000 is billed in January, I want my originations report to show $10,000 added into John's total originations and $10,000 added into Bob's originations.  And still show the details of that total broken down by timekeeper which also is split 50/50.

Is that possible?