If the interrupt controller vectors directly to the appropriate interrupt handler, each of the ISRs that are actually used in the application must be written in assembly language as described in Typical µC/OS-III Interrupt Service Routine (ISR). This, of course, slightly complicates the design. However, you can copy and paste the majority of the code from one handler to the other and just change what is specific to the actual device.
If the interrupt controller allows the user to query it for the source of the interrupt, it may be possible to simulate the mode in which all interrupts vector to the same location by simply setting all vectors to point to the same location. Most interrupt controllers that vector to a unique location, however, do not allow users to query it for the source of the interrupt since, by definition, having a unique vector for all interrupting devices should not be necessary.