There is a place where a lot of the studs in the multiengine/P-3/C-130/etc pipeline went following winging to get mil equivalency tests. Only thing I heard of was Commercial/IR tickets with type ratings for King/Super King Airs (T-44 and TC-12). Could be the same place works a deal for ATP as well, though I never heard of that. I presume you are talking about coming in as a winged aviator with the ATP hour minimums? Pretty sure everyone I have known to cross over into civilian airline type stuff had to take an ATP check ride like everyone else, and had the requisite hours as well.