I have an idea for a single magic item that can cast a variety of spells a limited number of times - is it possible to make something like that in the Homebrew creator? 

My original idea is this:

Wand of Watercolours, Rare
The tip of this multicoloured wand resembles the tip of an artists paintbrush. By flourishing this wand in the air, you can cast the following spells a limited number of times (using your spellcasting ability and spell save DC)

Minor Illusion - at will
Color Spray - 9 charges
Hypnotic Pattern - 4 charges
Major Image - 3 charges
Hallucinatory Terrain - 1 charge

So with this item, you could only cast Hallucinatory Terrain once, but you could cast Major Image up to three times. The flavour being that there is only so much "paint" on the brush. Sort of like having one scroll of Halluncinatory Terrain, three scrolls of Major Image etc... but all contained in a single item.

I can't figure out a way to assign a number of charges per spell to draw from a total charge-pool that doesn't feel clumsy. The other alternative is to limit it further and have it recharge each day with attunement, but I like the idea of it being consumable.

Any suggestions or tips would be hugely welcome.

Thanks in advance! :) 

Give the device a total of 9 charges. Make Color Spray cost 1 charge to cast, make Hypnotic Pattern cost 2 charges to cast, make Major Image cost 3 charges to cast, make Hallucinatory Terrain cost 5-9 charges to cast. 

Otherwise make them each “X uses” instead.

Is this intended to recharge every morning like a wand?

My intention is not to have it recharge.

With this solution, won't each spell consume charges from a pool? For example, if I had cast Major image twice, using up 6 charges, would I still be able to cast Hallucinatory Terrain?

Quote from RossExton >>

My intention is not to have it recharge.

With this solution, won't each spell consume charges from a pool? For example, if I had cast Major image twice, using up 6 charges, would I still be able to cast Hallucinatory Terain?

 You are correct, each spell would consume charges from a pool. I think this solution would actually make it feel more like total amount of “‘paint’ on the brush” that you had described, and you could always adjust charges/costs to better suit you.

If instead of total “‘paint’ on the brush” you want it to act more like total number of “paintings” and of what types, then instead of “charges” switch to total uses for each option.

Yes, I think I might have to use a total pool and adjust the number of charges to make it work. Thank you for your help clarifying :) 

You could just list each spell working “X times,” there’s just no mechanical way to make it work. It would be description only.