I believe that this would be allowed as long as these clans are distinctive in nature, and have their own separate plots.
However, I believe that if these clans would collide in one way or another (for example, the gathering that you mentioned) that it would be appropriate to stick them in the same roleplay thread so it's organized and it would be less confusing.
Therefore, if the clans do merge in the same plot at whatever time, perhaps that one discussion thread would be more suitable to discuss about the gathering more efficiently?