Interesting you should ask this, because I came across my old copy of Daniel from Artscroll over shabbos.

Quote:
In particular I am interested in the "they".


According to Rashi and Ibn Ezra, "They" refers to the different nations; they will intermarry with each other, but these intermarriages will not cause a mixing of the religious, ethnic and racial divisions. Each group will remain separate, just as iron and earthenware do not mix.
According to R' Saadiah Gaon, the nations will intermarry, but the marriages will not cause them to love one another. There will still be hatred and strife.

regards