How to swap one stitch inside a distributed group of stitches
Hold Alt, click one stitch of a distributed group and Swap it for the standing chain. The group and the ring stay whole.
Steps
Distribute a combo around a magic ring, for example a semicircle of 2 double crochet, a chain 3 arch and 2 more double crochet, four times.
Hold Alt (Option on a Mac) and click one double crochet. Only that stitch is selected. Its group and the ring stay as they are.
Press Swap on the small toolbar above it.
Type chain 3 in the box and click Chain 3. The stitch becomes the standing chain, and the whole group is selected again.
Drag the ring or one of the other copies. The whole round moves together, including the standing chain.
Try it here
Good to know
No Ungroup needed
A plain click always selects the whole group. Alt is the one way to pick a single stitch inside it, so you never have to ungroup, swap and regroup.
Swap all
The Swap stitch box has a Swap all switch. Leave it off to change only the stitch you picked, which is what you want for a standing chain. Switch it on to change the same stitch in every copy.