When Haldir first meets Frodo and Legolas in Lothlórien, he says
... for we now dwell in the heart of the forest, and do not willingly have dealings with any other folk. Even our own kindred in the North are sundered from us...
From this it seems like there were groups of Elves who do not get along, though it is hard to believe. Is it just lack of communication due to dangerous times and long distances between the groups, or was there some sort of falling out between groups of elves?
They do seem friendly enough to Legolas and they seem to communicate with Elrond. In what sense does Haldir say 'sundered'?