I'm not following, you want to connect several microphones?
Typically, if you want to go through 3.5mm jack, it will depend on your sound card and how many ports you have. Some laptops have 2-3, but you can configure each jack as to what you're plugging into it depending on the sound card (some sound cards don't have such features)
So, in case your sound card doesn't have such features, you can get a USB hub and get a bunch of USB microphones. Since they aren't going to be connected via a sound card you might have some trouble getting them all configured though.
As WR2 suggested you can also get an external sound card, that would allow to connect several microphones at once.