text: Chapter 1
  be inappropriate for the brigade to be subordinate to the battalion; hence, the echelon uses an Army
  support relationship.
  * The supporting unit supports several units simultaneously. The requirement to set support
  priorities to allocate resources to supported units exists. Assigning support relationships is one
  aspect of command and control.
  1-50. Army support relationships permit supporting commanders the ability to employ their units’
  capabilities to attain necessary results by supported commanders. It is extremely critical to have HR support
  capabilities flexible enough to be closer to enable commanders in making important decisions and assessing
  risks about HR support or manpower. Support relationships do not alter ADCON. Commanders specify
  change support relationships through task organization. See FM 3-0 and FM 4-0 for further information on
  Army command and support relationships.
  HR AND THE SUSTAINMENT WARFIGHTING FUNCTION
  1-51. For HR support, all HR functions and tasks integrate under the sustainment warfighting function. It is
  important for sustainment leaders and staffs to understand the HR and sustainment relationship as it relates
  to supporting and supported roles and responsibilities. Supported organizations include corps G-1/AGs,
  division G-1s, and brigade and battalion S-1s. Supporting organizations include the human resources
  operations center (HROC), theater personnel operations center (TPOC), expeditionary sustainment command
  (ESC) distribution management center (DMC) human resources operations branch (HROB), DSB and
  sustainment brigade support operations (SPO) HROBs, division sustainment troops battalion (DSTB) SPO,
  theater gateway personnel accountability team (TG PAT), military mail terminal (MMT), and HR companies.
  Figure 1-4 provides an overview of HR organizations and their relationship with sustainment units and
  supported units within a theater of operations.
  Figure 1-4. Human resources and sustainment structure relationship