lstBullets = {}

function AddBullet(ptype,px,py)
    table.insert(lstBullets, {type=ptype,x=px,y=py})
end

AddBullet("player",10,10)
AddBullet("ennemy",10,10)

for b1=#lstBullets,1,-1 do
    local bullet1 = lstBullet[b1]
    if bullet1.type == "player" then
        for b2=#lstBullets,1,-1 do
            local bullet2 = lstBullet[b2]
            if bullet2.type == "ennemy" then
                if bullet1 ~= bullet2 and Collide() == true then
                    if bullet1.type ~= bullet2.type then
                        -- Collision entre 2 types différents
                    end
                end
            end
        end
    end
end