A few weeks ago someone had asked about SOG Abn insertions. My reply was that they may have been attempted but were not IMHO practical because of the necessity of recon teams to stay together. Below is a declassified document from that period. Note that one HALO and four static line operations were conducted. Even though the staff in the "Puzzle Palace" determined these to be viable means of insertion, all five operations were aborted since the personnel became separated upon insertion.
http://www.gwu.edu/~nsarchiv/tailwind/twc.htm