Can a Gargantuan Object that is divided into parts be Animated as distinct parts?

Question

I'm GMing a group of players for the second time. Most of them were first time players on the first go, and are now feeling more confident in their D&D skills. We've decided as a group to keep to RAW and I want to honor that decision for world building and NPC creation as well.

This is a follow up question to another similar question I asked, however this question is different and stands on its own.

I'm hashing out a collective of NPC Rock Gnomes who live in a small stone castle shaped like a Huge person, about 15 x 15 x 22 feet, which is the maximum size for a creature of Huge size. This collective of gnomes will have two basic talents that they excel at one of which will be:

• They can animate their castle and enlarge it both to travel short distances and as a defensive measure against creatures of ill intent.

I've already asked what would happen if the castle is enlarged to Gargantuan after it's animated and RAW indicate it would Deanimate.

My question here is:

• If a Gargantuan Object is divided into 3 distinct parts, can each of those parts be animated separately?
• And as a follow-up secondary question, is there a way to change the Separateness of the three parts so when they are enlarged they can be enlarged together, and then animated separately?

So using the design above, when the castle is enlarged to gargantuan, the arms, legs and body would each be animated separately since they are only Huge Objects on their own.

And applying the follow up question would mean: The castle would be enlarged using a single Enlarge/Reduce spell and then the legs and arms would somehow decouple mechanically so they can be animated separately.

Animate Object states (PHB 213):

You can’t animate any object larger than Huge.

Enlarge/Reduce states (PHB 237):

The target’s size doubles in all dimensions, and its weight is multiplied by eight. This growth increases its size by one category—from Medium to Large, for example.

Answer 1

The premise is somewhat flawed...

From DMG p. 246 (or the corresponding section of the basic rules):

For the purpose of these rules, an object is a discrete, inanimate item like a window, door, sword, book, table, chair, or stone, not a building or a vehicle that is composed of many other objects.

The "not a building or a vehicle" part kind of means that the entire reason for the question is against the rules.

But lets assuming that the building is made out of solid rock and therefore not "composed of many other objects":

1. The solid rock building gets enlarged from huge to gargantuan
2. The (still solid rock) building cant be separated into three solid rock parts within the duration of the spell the enlarge spell is un-enlarged due to the target no longer being valid (whether suppressed or removed)...
3. If the gnomes somehow got the castle into three parts they cast animate object on the three parts and go on their merry way.

On the other hand this would be possible by enlarging each part separately then animating them separately. This would require 2 casters per object to maintain concentration and they would not be attached.