Like giving a Ghost-type the Ring target, enabling Normal and Fighting moves to hit it, would it work the same for Ground vs. Electric, Dragon vs. Fairy, or Poison vs. Steel?
Yes it would.
Source: Experience
This item, when attached to a Pokémon, allows the Pokémon to receive damage from the opponent regardless of any type immunities.
Source: http://www.serebii.net/itemdex/ringtarget.shtml
The holder loses its type immunities.
Source: http://bulbapedia.bulbagarden.net/wiki/In-battle_effect_item
If a Fairy type is given a Ring Target the effectiveness of Dragon is 1x. If a Steel type is given a Ring Target the effectiveness of Poison is 1x. If a Ground type is given a Ring Target the effectiveness of Electric is 1x. If a Ghost type is given a Ring Target the effectiveness of Fighting and Normal is 1x. If a Dark type is given a Ring Target the effectiveness of Psychic is 1x.
Note: The effectiveness above is for Pokémon that are pure of that type, such as Florges is a pure Fairy type so the effectiveness of Dragon would be 1x if it was holding a Ring Target.
Hope I helped :)