2.5 Notification to representatives 

If a representative has been appointed, notifications must be addressed to them. If several representatives have been appointed for a single party, notification to any one of them is sufficient. If several persons are joint applicants for or proprietors of a patent or have acted in common in filing notice of opposition or intervention and have not appointed a common representative, it will again be sufficient to notify one person, namely the person referred to in Rule 151. If several parties have a common representative, notification of a single document to the common representative is sufficient.