[RMMV] NEED HELP WITH A SPECIFIC PARTY & BATTLE SYSTEM

Hi! The game I'm working on (using RPG Maker MV) has 20 characters. But I'm wondering if it's possible (and if so, how) I could have it so that the player could choose 12 of those members to take into a dungeon, but only 4 could be used at any given time (with party members being swapped within battle from those 12).

The idea is that there's basically three groups that the party is split into.

Front lines(active members who are participating in battle), back lines(still in the current party but not in battle, can be switched in mid-battle), and reserve(can't be used unless you switch them into your party at the hub).

I was wondering if this was possible using Yanfly's PartySystem plugin, but from testing that one out, I can't seem to do it. But if I can use that plugin, or if there's a different one out there, I'm willing to try them.

If you've played it, I'm thinking something like Labyrinth of Touhou 2.

References images also available.

Screenshot 1

This screenshot shows a party member change menu, where you can choose to change your party. Only available in the hub area.

Screenshot 2

The top part of this image shows the party members you have selected and the bottom part shows the available party members you can add. This would be before entering a dungeon.

Screenshot 3

This screenshot shows what it's like in battle. Selecting 'Form Change' would allow you to bring up your current active party. Screenshot 4 shows this menu.

Screenshot 4

This screenshot shows the party. The bottom row shows the current active battlers. The middle and top row are the back lines.

If none of this is really possible without a brand new plugin made, is there anything out there that might be similar in some way? Thanks in advance for any help!

author=Marrend
Setting aside Yanfly's party system for a moment, being able to swap party members mid-battle would mean including various classes/functions/variables that exist in Scene_Party, and moving them wholesale into Scene_Battle. While I might have some familiarity of Yanfly's party system for Ace, I'm not sure what all functions Yanfly includes in their MV code, so, I will not dare to comment further as to what all items would be needed.

As for selecting party members from a list of 20 down to a list of 12? The thought in my head is that you might be able to use...

$gameParty.members().length = 12;

...this line of code after calling the party menu as normal to cut down the party size down to 12. Re-adding the cut members afterward could be done through a function-call, which could look like...

function partyReset() {
  $gameParty._actors = [];
  for (let i=0; i < $dataActors.length; i++) {
    $gameParty.addActor(i);
  };
};

...this? That should reset the party structure to being sorted by their ID as defined in the database. Which might not be ideal, but, it's the least complex solution I can think of.

Thanks for the response! I'm not exactly sure where I need to put these as I know absolutely nothing about programming plugins. I looked around in the code to see a logical place to put them, but I'm not sure where. Any advice on that would be very much appreciated!