how to set a 5424 to work as a repeater for a vlan trunk?

Hi,

I need to find a solution for my configuration.
in my configuration i have 3 switches  one on side A one on side B and one AB in the middle because the range of A and B is just over the limit of enhernet.

Swicht A and B are configured and working as it should, but the thing is that the switch on side B is going to be replaced on another level in our building, and it reaches over the maximum of ethernet.

Switch AB is my solution to place this switch in the middle as a repeater. But how must i configure this switch.

Switch A is connected on port 23 and switch B is connected on port 24.
on side A there are VLAN configured and they are trunked to side B.

How can is configure the 5424 to work as a repeater for the VLAN trunk?

many thanks in advance!

Greetings Arnaud