According to Art. 99(3) EPC, opponents are parties to the opposition proceedings as well as the patent proprietor. It is clear from this provision that multiple admissible oppositions do not initiate a corresponding number of parallel opposition proceedings but only a single one. Each opponent can rely on an opposition ground duly submitted by other opponents and communicated to all parties in accordance with R. 79(2) EPC, both in the opposition proceedings and in any subsequent appeal proceedings (T 270/94, T 620/99, T 774/05).