There is an option through group policy preferences GPP you can use it . This solution is based on environment variables to find groups or users to be added in the local administrators group based on computer name %computername%.
For more details please refer to the following article: https://blog.jonasdahlgren.se/2022/03/14/gpo-and-local-administrator-group/
If you cannot use this option, unfortunately you have to add them one by one in group policy preferences and use items targeting option.
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