Block isp pppoe server from Seeing each others

hi i run a small wireless network from one isp provider over pppoe (i buy pppoe users and sell them),
now i try to get another isp provider to my network (over another pppoe server) but the problem is the two provider (two pppoe server) can reach others over my network. is thier a way to block that.
test222.png

USE VLAN

How i can do it, i try many ways but not working
Can u help me