Near the end of the Seder, after Hallel, we say "The Seder has ended..." followed by "Next year in (rebuilt) Jerusalem". But strangely enough, the Seder does not end here. It continues with a bunch of random songs with no apparent order or common theme.
At the same time, unlike at Shabbat and some holiday meals, during the "Shulchan Orech" part of the Seder, nobody I know has ever sung any kind of zemirot.
Perhaps you could avoid both of these weirdnesses by singing the songs of Nirtzah as zemirot during the meal...
If I'm ever in charge of running a Seder (probably not for several years at least) I might just try it.