use ext_pillar data accross Salt Syndic nodes

[mmgit]

Hi.

We have a Saltstack environment with a salt master and two salt syndic nodes in different security zones. Now I wanted to use external pillars comming from a PostgresDB. That works for all minons directly connected to the master but not accross the syndic nodes.
The syndic nodes can't access the DB directly so the data has to come from the master.
We deploy the other pillar data stored in files with rsync to the syndic nodes.
Is there a way to achive this?