The " one.
Click that on the people you want to multiquote then go to post reply right at the bottom and then they all come up
Its the icon next to the work quote with the two inverted commas at the bottom right
x2 ive seen this done loads but i cant work out how too do it. i think it involves clickin that ikon next too the img one an copyin an pastin the text inbetween it.
but i could be wrong