We're building a spell that can target magical items, similar to mage's disjunction in Pathfinder. Fifth edition has a spell that targets spells affecting objects: dispel magic, but nothing that directly affects magical items, as far as I can tell. If we want to target magical items, it makes sense to give magical items a save (as in 3.5/Pathfinder).
The easiest way to do this is just to give the item an arbitrary saving throw, with a bonus for rarity. Better still would be giving it a Wisdom or Constitution save.
Borrowing from Pathfinder again (source):
Magical Items: Magic items always get saving throws. A magic item’s Fortitude, Reflex, and Will save bonuses are equal to 2 + half its caster level. An attended magic item either makes saving throws as its owner or uses its own saving throw bonus, whichever is better.
Is there a similar rule in fifth edition? How do you determine a magic item's saves?
Note: I'm not talking about sentient magical items. I'm looking for a rule to apply to regular magical items. Sentient magical items would likely get a bonus though.