When it comes to structure placing in multiplayer game, only non-player-character Crafters could be selected to form a facility, either with or without the direct involvement of player driven Crafter giving the order, as part of the resources available. Tertiary player driven units, although generally selectable, are unmanagable in the range of structure composing, equipment customizability and other - if any - remote unit control options.
When multitude of units is selected at once, for example in Satellite View - be it a homogenous or heterogenous group, in singleplayer or multiplayer - on the left side of the screen a summary should be displayed, composed of symbols of the types of units selected, as well as numbers attached to these symbols, indicating how many of given kind are included. Non-player-character Crafters have own symbol, but player driven Crafters have a distinct one, in order to be easily selected out if demanded. Left clicking on given symbol allows to lower the amount of units of the type selected, according to the chosen pattern of disincluding. Right clicking unfolds a menu describing given symbol - the menu contains patterns of disincluding: weakest health, highest health, weakest firepower, highest firepower, weakest PSI, highest PSI [temporal]. If all units are equal against the criteria, disinclusion is random. All the units selected and featured as symbols and numbers on the left side of the screen could be attached to a groupmark, represented by a keyboard function key.
The Armory without the Factory may work and react to the techtree progress on regular basis, though Factory without Armory, not - apart from the manufacture of light tier units - as on the higher levels of progress, only empty crafts could have been produced under such circumstances, questioning the purpose of making them even choosable in the production menu.
Perhaps I think shallow, as weapons could also be produced in the Factory only for the sake of units, as the main point of Armory is to deliver the items deep into battlefield. So should Factory be anyhow dependent on Armory, or is the Armory to be mostly a selfstanding independent facility?
The techtree, the secondary constructs - consisting of various structures attached mostly either to the grid of Factory or Armory - expands without any further tierbased dependencies, suggesting only the Scrap to be the limit, as long as either the Factory or Armory given construct demands is available.
One way is to assume the techtree constructs should demand particularly either the Factory or the Armory, providing some kind of idea of a techtree into the game. Other way is more easy, meaning any secondary facility needs to be connected to a grid of any of the two mentioned key buildings, without further requirements. In the end, the latter solution implies either the Factory or Armory could be omitted entirely in the play, if that suits the strategy.
Post edited in terms of selected unit group automatic disinclusion menu options.