Can I use two geosyncronous satellites to satisfy the formation flight tasks?
No. The intent of the formation flight tasks is to location and track two (or more) objects that are deliberately flying in close proximity to each other. In the case of geosync satellites, the fact that any two are near each other is coincidental, as they do no rely on being near each other to complete their respective missions. Similarly, two satellites that happen to pass near each other (in different orbits) do not qualify for the formation tasks. The likely candidates for formation flight are ISS and Shuttle missions just before docking (or just after separating), or payload/booster pairs just after staging.
