If we want to upload gangelements without massive xrefs, they need to be inlined.
We already use Resources as elements (see e.g. Device)
Table 6.164: GangElement Element
|element|| Media definition whose characteristics SHALL be met in the
|element|| <copy from ref>Reference to RunList SHALL specify the content data for this GangElement. If this a RunList refers to a
structured PDL with multiple document instances such as recipient records in
PDF/VT, then this GangElement represents multiple individual sections.
These sections SHALL be positioned using the same rules that would apply if
each document instance were referenced by an individual GangElement. All
document instances referenced by an individual GangElement SHALL be processed
in one gang.