If one in finished his amida and there is someone still in middle of his amida behind him, Im under the impression that we wait for them to finish before stepping back. So before we say the final yehihu leratzon before stepping back we pause there and wait. What can we say while we stand there and wait? For example, now is chanuka, can we say hallel with the minyan and then step back whenever he finishes his amida behind me (even if we are in middle of hallel)?