There is no server communication needed, since the position of the players is already synced.
You need to check it per player.
And use another table structure.
Something like this would do:
local linePoint = {
[player thePlayer] = {
{float x, float y, float z},
{float x, float y, float z},
{float x, float y, float z},
{float x, float y, float z}
}
}