Hello,
i want to build a not-so-transparent bridge between 2 networks, the thing is that i don't want both networks to have full visibility.
so i want to filter the MAC that can access the bridge on each side of both networks.

can i do this with routeros in WDS bridge mode?, how?

All traffic that comes through a bridge (as opposed to forwarding between the clients of the same AP), like in your configuration, between two WDS or between a WDS and an ethernet, can be filtered. check bridge filter menu to see the options