1. A method of allocating resources to system images in a logically partitioned data processing system, the method comprising the computer implemented steps of: evaluating an input/output adapter to determine if the adapter has sufficient adapter resources for respectively allocating a plurality of resource groups to each of a plurality of system images, wherein each resource group of the plurality of resource groups respectively comprises a portion of the adapter resources; and responsive to determining the adapter has sufficient adapter resources, respectively assigning each of the plurality of resource groups to one of the plurality of system images, wherein adapter resources of a resource group are exclusively available to a system image of the plurality of system images to which the resource group is assigned.