Relative submodule URLs

The documentation wasn't 100% clear on this, but I'm assuming by "remote origin", it says that the relative URL is relative to the actual remote *named* origin (and it is not using origin as just a general terminology).

Is there a way to specify (on a per-clone basis) which named remote will be used to calculate the URL for submodules?

Various co-workers use the remote named "central" instead of "upstream" and "fork" instead of "origin" (because that just makes more sense to them and it's perfectly valid).

However if relative submodules require 'origin' to exist AND also represent the upstream repository (in triangle workflow), then this breaks on several levels. There is also the common issue of upstream submodules needing to be forked as well.

Would like to see if there is a way to workaround these issues with Git 2.1.0

Thanks in advance.