You cannot get help with storing a spell
The glyph of warding spell states:
[...] Spell Glyph. You can store a prepared spell of 3rd level or lower in the glyph by casting it as part of creating the glyph [...]
This shows that "you" (the caster of glyph of warding) must cast the stored spell when creating the glyph, not somebody else.
That said, houseruling this as an option probably won't break your game by any means. It does let the party split up the spell slots required and it makes it so that only one member of your party needs to know the spell for them to make full use of it. This is a flat buff to the spell.
One potential problem is that this allows spells from classes that ordinarily can't get glyph of warding to store those spells in the glyph. I don't believe this would have significant impact and it is technically already possible through the Bard's Magical Secrets feature but that's a much higher tax for the Bard.
An additional benefit mentioned by user @Vigil is as follows: Say casters in the party only have one fifth level spell slot, ordinarily then, you could not store a fifth level spell, but now you could by having separate casters use up their own separate slot. This always applies to ninth level spell slots, and to any spell level for which the party's casters currently only have one slot. Note that doing this is technically already possible if a Sorcerer uses their Flexible Casting feature (though this only works for spell levels 2-5), and again, like the Bard, there is a much higher tax for the Sorcerer (Sorcerer's do not ordinarily get this spell so they would need to multiclass).
The houserule buffs the spell as only one member of the party needs it, and it allows spell slots to be split up as well as allowing any spell to be stored. It also makes the the rather niche uses mentioned above available to all casters, not just Bards and Bard-Sorcerer multiclasses.
