Question
Is it permitted by the Torah to give away a part of our G-d-given land in the hope of peace?
Answer
In principle, we do anything except for three cardinal sins (murder, adultery, and idolatry) in order to save even a single Jewish life – we break the Sabbath, we eat pork, etc. In fact it is a mitzvah to do so.
Therefore, the question comes down to this: Will this action save Jewish lives? A definitive statement on that is already beyond my expertise.