then the best way to do it is the usage of dedicated derivation path for each set of addresses
While the derivation path is indeed an elegant approach, I find it somewhat advanced and people may get headaches if they use them without understanding what they do. Those headaches could come when they'll want to recover their wallets, at some later point.
Can you talk a little more about these retirement accounts. You say that the retirement accounts hold the coins, but if you have the private key then you would hold coins.
Indeed. OP, can you please explain in more words what you intend to do and how (if possible), since you may have misunderstood something and it would be best to have everything crystal clear before changing anything.