Don't dry hop. Bottle and leave for 6-9 months,or more. The bitterness will decrease noticeably with time. A beer considered much to "bitter" or "hop tangy" will be quite mild and enjoyable after one year.
If the beer must be drunk or thrown then try adding some non fermentable sweetener like lactose or stevia to a test pint. Some times the sourness/bitterness of the hop can be balanced against a sweetness, usually from the malt."Sweet and sour" tastes are quiet appealing on the tongue so maybe its possible to repeat the trick with the bitterness of the beer. One might try adding malt extract as the obvious sweetener but further fermentation might alter the taste again.
EDIT: If one doesn't have enough glass bottles then it is better to use plastic carbonated drink bottles then discarding the brew. Plastic isn't good for very long term storage but it will allow conditioning of beer for 6 months without too much loss of pressure.