Okay, here's a hypothetical situation. I have Abyz-Fria. No fool I built a space dock on each world. I want to add two ground forces to the system, one to each world. I try to do this during production. Since GF are placed on the world associated with the space dock that built them, can I split that pair, claiming one was produced at each SD, while still only spending one production for the pair of them?

No, you can't do that. Rules are quite clear on this., p. 26:

• Ground Force and PDS units are always built and
placed on the planet containing the Space Dock.
Ground Force and PDS units cannot move to another
planet (including other planets in the same system)
unless transported by a Carrier or War Sun.

This question comes up quite often in our games as well. Some people are frustrated by this, by IMO it is an essential part of game mechanics - you have to know how to handle your logistics to protect each important planet.

The thing is in this example BOTH worlds have a Space Dock, since the system's production is so high. I guess I'm asking when you buy a pair of GF for a single production point are they treated like a single unit for placement (ie, both must be produced at the same SD), or can they be split between two SDs in the same system?

When you purchase Ground Forces you buy 1 or 2 at a time for the cost of 1. (Yes you could only buy 1 if you are at your Production cap and can only buy one more unit.)

When you build the 2 Ground Forces they are a single purchase and are bought at 1 Space Dock only and are placed on the planet that that Space Dock is attached to. The build is not split up as each Space dock builds separate from each other. This is why it is nove to have multiple Space Docks in a system and have Sarween tools as each will get the extra 1 for building at. A great way of placing the 2 Ground forces at each planet without spending any resources.

i agree with Tawnos and magicoctopus. Building 2 GFs for 1 Resource is a "package deal". Just like you can't split a Cruiser between two Space Docks, you can't split this GF "package" between two docks, either.

If you want to build 1 GF at each dock, you'll have to pay the 1 Resource for each.

Another way to look at it is this:

Each Space Dock builds its units completely independent from the other. Thus, for each individual dock, you calculate the total cost of the units produced from that dock by itself. If you have Sarween Tools, you can reduce the price for the dock's production by 1.

Then after you've figured out what each dock is building, and the cost for each separate dock's production, you combine the cost, and can then pay for that combined cost however you like. (noting that Sarween Tools is factored in prior to this already, emphasizing that you can't "combine" Sarween Tools usages to build one big ship with it for free).

Thus, with the GF example, you look at Dock 1. It builds 1 GF. When building that GF, it costs 1 whole resource, not 1/2 a resource, when figuring the dock's total. Then you look at Dock 2; it also builds 1 GF. It also costs 1 whole resource, not 1/2, toward that docks total. Then, when you combine the costs, you have 2 Resources (plus whatever else you are building).