EU commissars are not directly elected officials, no, but they are also not "named by a totally informal group". 'EU Commissars' (typically called an European Commissioner) are nominated by their member state, one each. The European Parliament then votes on the whole. So they are still under democratic control: through the various chosen governments of the states, and through the EP.
The Eurogroup -- a discussion body for the 19 states that use the Euro as currency -- had nothing to do with the SWIFT ban. (it does have a bunch of issues from a democratic perspective, although it seems like most of the members are just their country's finance minister... which makes sense for a discussion forum about the Euro?).