[SOLVED] How to detect when a group of objects collide with another?

I want this script to work only when one or more of Char's objects collide with one or more of Surface's objects. It would also be useful to have a table (SurfCol) of the objects that are colliding specifically in the Surface table. How can I do this efficiently?

-- Settings --
local GlobalFrequency = 10

while true do
    local TickA = elapsedTime()
    wait(1/GlobalFreqency)
    local Surface = game.Workspace.ImprintableMap:GetChildren()
    local Char = game.Workspace:GetChildren()
    for i=1,#Char do
        if not Char[i]:FindFirstChild("Humanoid") then
            table.remove(Char, i)
        else
            print("Found NPC " .. Char[i].Name)
        end
    end
    for i=1,#Surface do
        for l=1,#Char do
            local DetectDistance[l] = (Surface[i].position - Char[l].HumanoidRootPart.Position).magnitude
        end
        local DetectDistance = math.min(DetectDistance)
        if DetectDistance >= (Surface[i].Size.X + Surface[i].Size.Z)/2 + 5 then
            table.remove(Surface[i])
        end
    end
    if DetectDistance ~= nil then
        for i=1,#Char do
            for l=1,#Surface do
                local x[1] = Char[i].LeftLeg:clone()
                x[1]:ClearAllChildren()
                x[1].name = CharSub[i + l]
                x[1].parent = game.Workspace.ImprintableMap
                local x[2] = Char[i].RightLeg:clone()
                x[2]:ClearAllChildren()
                x[2].name = CharSub[i + l + 1]
                x[2].parent = game.Workspace.ImprintableMap
                local Imprint = Surface[l]:SubtractAsync(x)
                Imprint.name = SnowPlane
                Imprint.parent = game.Workspace.ImprintableMap
            end
        end
    end
    local TickB = elapsedTime()
    -- Remove this code --
    print(TickB - TickA .. "ms")
    break
end

I ended up measuring how far the Char's and Surface's are and if they are too far away not executing that part of the code.