re non mevushal wine

Question

Dear Rabbi, Not offended at all by your response( you are usually so calm :-) ), although the question still remains. I often entertain non-observant relatives and friends. I usually, as a preference and maybe halacha, only serve non-mevushal wine. If I pour it for them, it`s kosher. But it`s not always convenient, especially at Pesach to do this. If, as I do, suggest each pour his or her own wine, am I putting a stumbling block in front of the blind by doing that. Thee bracha question was extra. If I make kiddush for them on wine they have poured for themselves, is that a problem? Many of mu guests want to do the right thing and will ask what the correct bracha is on such and such, and if it`s now on non-kosher wine, should they say it? ( obviously if I`ve said kiddush for them I`ll tell them it`s already done. Cheers, And Chag sameach, Martin