hudi
B”H you haven’t lost the sensitivity to Tznius (and mentshlichkeit) as is obvious from your last post. Unfortunately, I cannot say the same for some of the other posters.
Regarding your question: I think that a good way to inform your male classmates about your hands-off rule, is to wait until you are in a group project situation like you mentioned, and in a light, casual way let eveyone in the group know that as an orthodox jew you are prohibited by Torah law to have physical contact with the opposite gender.
Smile while you say it (NOT APOLOGETICALLY!) in a way that says “I’m not trying to make a big deal out of this, let’s keep the mood here comfortable; and I can still take part in group discussions like everyone else.” But make sure you sound firm.
(Sort of like when you would explain to your co-worker why you cannot enjoy the box of chocolate that she brought you for New Years. Friendly but firm.)
They most likely never heard of this before, and may ask questions or be a little awkward around you in the beginning. But keep up a friendly, albeit slightly distant demeanor and they’ll realize you’re actually normal! (except for this wierd no-touching religious quirk…)
Btw- Don’t forget to ask Hashem for Hatzlacha!
I envy your opportunity here to make such a tremendous Kiddush Hashem.
Good Luck!