Call me a lawyer but a friend of mine raised an interesting question. Can a single sponno element be halted while forming part of a sponno group not halted this bound? The relevant rules are:
A halt applies to all elements of a group (even if they join it later), so it is not possible to halt only part of a group and subsequently allow spontaneous advances by other parts.
Are these "other parts" subgroups only?
Thank you in advance.