If I have not yet finished praying but the congregations has - if the hazzan began reciting psalms for the safety in the state of israel, do you interrupt your prayers and join in with the congregation or do you finish your prayers and then say what you can with the congregation or by yourself?
Ketoret and Shir Shel Yom do not seem to be requests. Additionally they do not need a minyan to say them.
The Gemoro Brochos 8a indicates that Hashem does not despise the prayers (requests) of the many.
רבי נתן אומר מנין שאין הקב"ה מואס בתפלתן של רבים שנאמר הן אל כביר ולא ימאס
Soncino translation of the Gemoro:
R. Nathan says: How do we know that the Holy One, blessed be He, does not despise the prayer of the congregation? For it is said: ‘Behold, God despiseth not the mighty’.
R Nathan understands “the mighty” to refer to the many who pray to Him.
It seems therefore that when we are requesting peace in Israel, we do need “the many”.
So it seems that it would be better to join in the Tehilim and requests for peace and finish off the other parts of davenning later.