Avoid route trought some subnet with automatic DAC created

RouterOS Beginner Basics
1

Hi,

I’m new in Miktrotik world!
I have a RB750Gr3 and i would like to route traffic between 3 different subnet (It’s an simple example)

I add interface

add address=10.1.2.1/24 interface=ether2
add address=10.1.3.1/24 interface=ether3
add address=10.1.4.1/24 interface=ether4

Device A is connected to Mikrotic ETH2 and has 10.1.2.10/24 and GW 10.1.2.1
Device B is connected to Mikrotic ETH3 and has 10.1.3.10/24 and GW 10.1.3.1
Device C is connected to Mikrotic ETH4 and has 10.1.4.10/24 and GW 10.1.4.1


Dynamic routing rules DAC have been created automatically for eth2, eth3 and eth4.
With these automatic rules all devices see each other end I can’t remove this roule with static route.
I can’t prevent device B from reaching device C and vice versa.

My goal is to make sure that there is two-way communication between device A and device B and between device A and device C. Devices B and C must not see each other!

Thanks to all Mikrotik community!
Example.jpg
Example.jpg