Help! 3 Vlan for two mikrotik rb750

RouterOS General
1

Hello! They can help me because I’m burning my head.
I need to transport 3 cablemodems with internet through vlans so that later through a radio link they reach 20 km and then take them with another mikrotik and then with 3 router for vlans divide the signal of each of the cable modems.
I need you to help me with the configuration of the vlan through the mikrotik. The 3 cable modems enter a rb 750 with DHCP.
I pass a graph to be clearer:
I hope you can help me because my head burned and I can not configure it. Thank you!!

Data: RB750 (A)

Cablemodem mouth 1 Routerboard
Cablemodem mouth 2 Routerboard
Cablemodem mouth 3 Routerboard

I leave for 5 to the AP

RB750 (B)

I arrive from the Client to mouth 1 of the RB
I leave by mouth 3,4,5 to another 3 intependiendes router so that they have internet.

2

Hello!
First, this task will be better suited by a switch with VLAN capabilities, you don’t really need a router to do this.

If you want to solve this situation with this hardware you need to use bridges between ethernet ports and GRE or EoIP tunnels.
So that you must have:
[ether1–bridge1–gre-tunnel1]—[wireless link]—[gre-tunnel1–bridge1–ether1]