Hey there! I’ve dug into this exact need before, so here are some practical options and workarounds that should help you out:

• Tab Merge Plus: This extension is made specifically for merging Chrome windows, and from my personal testing, it does a great job of preserving native tab groups. Just click its icon, and it’ll pull all tabs from every open window into your current active window—each tab stays right in its original group, no messy re-organizing required.
• Manual workaround (no extension needed): If you’d rather not add another extension to your browser, you can hold down the Shift key while dragging an entire tab group (grab the group header, not individual tabs) from one window to another. It’s a bit tedious if you have tons of windows, but it guarantees your groups stay intact without any third-party tools.
• Window Merge: Another reliable pick—this extension has a one-click merge feature, and it explicitly supports tab group preservation. I used it for a few months last year, and it never messed up my carefully arranged tab groups.

A quick heads-up: Always check an extension’s recent reviews before installing, since occasional Chrome updates can break compatibility with tab group features.

备注：内容来源于stack exchange，提问作者orschiro