Question: Florida Subscriber Answer: One condition you want to be sure to meet as a biller is that you must append modifier Q5 (Service furnished by a substitute physician under a reciprocal billing arrangement) to the code for the procedure the substitute physician provides. Group billing: For example, the manual explains that "On claims submitted by the group, the group physician who actually performed the service must be identified." The exception is that "When a group member provides services on behalf of another group member who is the designated attending physician for a hospice patient, the Q5 modifier may be used by the designated attending physician to bill for services related to a hospice patient's terminal illness that were performed by another group member." If the physicians in your group bill in their own names, treat them the same as independent physicians under the Medicare reciprocal billing rules.