Is Open-Salt Syndic topology supported by Salt-Support when used with SaltStack Enterprise (SSE)?
No. Salt-Support does not support Salt Syndic topology with SaltStack Enterprise (SSE).
SaltStack's Enterprise API replaces the Salt master syndic component to provide Salt minion aggregation and scale.
Salt Syndic masters are not compatible with the SaltStack Enterprise architecture. Instead, each root Salt master should connect directly to Enterprise API as noted in the Prerequisite Tab of the SALTSTACK ENTERPRISE INSTALLATION documentation.
SSE offers an Access Control List system to aggregate minions for control by named Administrators on the SSE system.
Of note, if one were to connect a Master-of-Masters to an SSE system (with Syndics below the MoM) the SSE system would see all minions under the MoM as part the MoM master, with no recognition of the Syndic segregation below the MoM.