scope based on belongs_to fields

I have a message model which belongs to a user and a club.

The club model has deleted_at and suspended_at fields. I currently have a method that returns all the messages for a given message type e.g. messages.where(:type => 'application')

What I am looking to achieve is to adapt that method to show that message type only if deleted_at and suspended_at are nil on the associated club model.

Im not sure whether its best to adapt that method or have a default scope that doesnt return messages if the club deleted_at or suspended_at are not nil.

I am also unsure how to adapt the method or construct a scope based on the above logic. Can anyone point me in the right direction?

The app is using Rails 3.2.