From what I can gather (which isn't too much) the US Marines formed six Separate Wire Platoons. The Amphibious Ops Handbook shows the units as Corps level troops along with the JASCOs, but I can find nothing on where they fitted into the Task Organization.
Were they normally attached to a Marine Div to augment the Div Sigs Co, or were they used alongside the non-Div assets? I've found one minimal reference in an Osprey title to suggest the former, but it might be an assumption rather than a certainty. The odd thing is they don't feature in the orbats for either Iwo Jima or Okinawa, which are both quite detailed and show numerous non-Div units of similar size. Is there a chance they were absorbed into the Div Sigs Co if they were routinely attached?