Some jurisdictions have specific legislation for holding companies (for example Luxembourg) and offer tax advantages, but most offshore jurisdictions, especially those that offer IBCs, do not.
This means that no special action is required from your end to create a holding company in for example Seychelles, since there is no distinction between trading and holding companies.
If you want Hartmut Holdings Limited to act as a holding company, simply tell your CSP that the shareholder (and director, if you choose) of Hartmut Trading Limited should be Hartmut Holdings Limited.