Replica Directory Node

Let’s say i have 2 sites with an unreliable connection (as in it might go down randomly for a day or so)
so in this remote site I decide to use a “Replica Directory Node” , that is a replica of a central home site.

now if this local copy needs to use a “trust” to another AD server in teh same building
is it possible to setup trust with this replica?
or does the trust have to be done from the central site, then replicate to the local copy ?