If you are from Windhurst and did the Bastok half of this mission first, you will fight this dargon.
If you are from Bastok and did the Windhurst half of this mission first, you will fight this dragon.
So long as you and your friends are slated to fight "this" dragon, you can all fight this dragon.
If some of your friends have already done their dragons, they can help you with this dragon.
Please remember, there is a level 25 cap. If you are any level above 25 and walk into this battlefield, you will be dropped to level 25 for the encounter. Please be prepared for that and have the appropriate gear, else you'll be naked.
I have a small group of RL friends playing FFXI. We didn't really do much planning, so we're pretty much all from different nations. If one of them from Windhurst has to fight the Dread Dragon (went to Bastok first), can we fight together? Or can I only fight with someone from Bastok?
(I understand the bit about Rank 3 folks, I'm just speaking of people still working on mission 6)