Based on this question.
Many (most?) Ashkenazim in America say Pesach, with a segol, when talking about the korban pesach, but Peisach, with a tzeirei, to refer to the holiday. As far as I know, the second version is not used in Tanach.
Based on Tehillim 119:130, I guess it would be more correct to say "Peisach Mitzrayim" and "Peisach dorot", but most people say Pesach even there because it's talking about the korban.
Since, the way people speak, Peisach with a tzeirei refers specifically to the holiday and not the korban, can you say "this meat is for Peisach"?