definitely, flame angel is quite aggressive to other dwarf angels. even though i had luck adding dwarf angels to existing flame, the first 2-3 days were always world war III.
you can rearrange the rocks to break the territory and hopefully the flame will leave them alone.
one word of caution about potter's angel. it's a very shy fish and doesn't do well with stress. i really recommend against putting them together with aggressive dwarf angels, unless the tank is big (> 300g).