there should be additional attacker sides to sieges to make sieges more dynamic and not so two sided.
a nation could siege an already besieged town by placing another banner upon the town or merging banners with the original banner by placing on the current bedrock platform/at most 32 blocks from the banner to avoid the new bedrock platform interfering with the first platform.
an attacking nation would be required to enemy the defending nation and current attacker nations. the multiple side sieges would only be as conquest and liberation sieges.
the sieges could be counted as entirely separate outside of war-sickness. the defenders could obtain a slight point multiple to compensate with dealing with more then one siege. deaths of attackers could give points only to defenders, or a large percentage of points to defenders and a small percentage to the other attacker side. deaths of defenders would be split evenly between attackers, or if the death was perpetrated by a attacker then their side would receive more points then the others.
defender victory could be achieved by beating each attacker's sides point totals separately, not combined. an attacker victory would be achieved by an attacker side having more points then the defenders and more points then any other attacker side, in the event of a tie between attacker sides then the tying side that entered the siege first would win.