Even if you don’t use Inkscape and Ink/Stitch to make your own embroidery designs, you can use them to do things like gang existing designs while keeping thread colors together. Here’s how.
When you open a stitch file (here, a freebie lip balm holder from Designs By Little Bee), Ink/Stitch will try to size the page based on the design and file info. First, you want to set the page size to your hoop size. It’s not strictly necessary (your design will end up centered on the hoop regardless) but it’ll keep you in bounds.
Next, open the Objects sidebar (Object > Objects) and click the Type icons (the column just shows T on mine) to convert them from groups (a yellow group “paper” on a white layer one) to layers (a stack of white layer “papers”). Here, I’ve done all but color block 1.
If you were to open the Layers sidebar (Layer > Layers) and click the main layer to see the sublayers, your color blocks are there. You don’t need to do that just to gang designs, though.
Now you want to select all the current stitches, across all the layers. Edit > Select All In All Layers will do that, as will dragging a box around all the objects. Either copy/paste or duplicate your selection. Drag it to where you want it. If you accidentally deselect it, undo and re-copy it to make sure you select all the parts.
For some designs you’ll want to invert every other instance. There’s no reason to do this for this design, and in fact flipping some will make placing the pockets more complicated, but for less-rectangular designs it can really help. If you do it with the rotation arrows on the toolbar each color will rotate on its own, so don’t touch those. Instead, either use the Object > Transform tool or click on the selection again to convert the handles to rotation ones. Holding down Ctrl will keep it constrained so you can rotate it exactly 90 or 180 degrees.
Keep duplicating and optionally rotating your designs until you have them arranged the way you want. Save your design as an Inkscape SVG in case you want to make future changes, then export it as a stitch file with Extensions > Ink/Stitch > Embroider. Make sure you choose the right format. You can set the destination to be directly to your USB stick if you’d like.
As part of the process, Ink/Stitch will create a new layer called Stitch Plan and (by default) hide your other layers. You’ll see the exact stitches, including jumps, that your machine will make. Ink/Stitch lets you set mid-color trims but in the interests of simplicity (and the fact that my machine doesn’t support them😉) I’m not going to cover that here.
To revert to your working SVG, you can just Edit > Undo, or delete the Stitch Plan layer and unhide the others.
(Big thanks to Lex Neva in the Ink/Stitch Github group for pointing out the object-to-layer thing; I had been manually creating layers and moving stitch groups to them for longer than I care to admit.)