filter groups in list

[cognosehelp01]

Hey guys,

I am trying to list vehicles and discrepancy events related to the objects.
I want to get when a vehicle came out of maintenance and any discrepancies in the 30 days after the event it came out of check.

I have a list with columns for Vehicle, date, and  whether an event occured.
I am using a detail filter that works off of the 'sign off date' + 30 days and it works fine for one vehicle.

Once I try to get multiple vehicles by model, since there are multiple maintenance checks the list seems to filter all of the vehicles for all the dates within the earliest point and the latest, instead of each vehicles respective 30 day period.

Is it possible to have the filter work for each individual vehicle I(I have tried grouping). or am I looking at this the wrong way by trying to jam all this info into single list? is there a better option?

Currently:

single vehicle:
vehicle 1 check sign off - 12/15/2014.
Post check period = 12/16-1/14.

multiple vehicles:
vehicle 1 check sign off 12/15/2014.
Post check period 12/10-1/14 (WANT: 12/16-1/14)
vehicle 2 check sign off 12/9/2014.
Post check period 12/10-1/14 (WANT: 12/11-1/10)