Buying for a crowd flips the priorities. At a wedding or a bachelor party you are not matching one person's palate, you are handing cigars to a room full of people, most of whom are not regular smokers. That makes mildness the safest possible choice. The single biggest favor you can do a mixed group is keep the strength down, because a full-strength cigar handed to someone who smokes twice a year will not go well.
So for a crowd I steer hard toward mild, smooth, approachable cigars. A Connecticut-wrapped mild is the classic move here for a reason: it tends to be gentle and easygoing, which is exactly what you want when you do not know who is smoking. Medium is fine for a crowd that skews more experienced, but if you are unsure, milder is the responsible default. Save the stronger sticks for the handful of friends you know can handle them.
The other reality of buying for a crowd is volume, and volume means cost. You are buying ten, twenty, thirty cigars, and at that quantity the price per stick matters a lot. This is exactly where buying online by the box beats single sticks at a shop, and where a solid value line earns its place. My guide to the best cigars under $10 is the right companion for this: it is full of long-filler value lines, including milder options, that let you buy for a crowd without the bill getting silly. A good mild value cigar bought by the box is the backbone of most wedding and bachelor-party cigar runs.
A couple of practical notes. Buy a few more than you think you need, because cigars get shared and lost and lit by people who were not planning to smoke. And have cutters and a couple of lighters on hand, because in a crowd most people will not have brought their own.