// Original interfaces
public interface IAudit {
  public string CreatedBy { get; set; }
  public DateTime CreationDate { get; set; }
}

public interface IOwnable {
  public string? Owner { get; set; }
}

public class House : IAudit, IOwnable { ... }

public class Form : IAudit, IOwnable { ... }

// DTOs / Mappers
// Assume that there are respective DTOs interfaces and classes
// IAuditDto, IOwnableDto, HouseDto (IAuditDto, IOwnableDto), FormDto (IAuditDto, IOwnableDto)

[Mapper]
public static partial class BaseMapper {
  public static partial void MapAudit(IAudit audit, IAuditDto auditDto);
  public static partial void MapOwnable(IOwnable ownable, IOwnableDto ownableDto);
}

[Mapper]
[UseStaticMaper(typeof(BaseMapper))] // Either have this automatically infer the usage of BaseMapper.MapAudit/MapOwnable
public static partial class HouseMapper {
  // Or allow this?
  [IncludeMappingConfiguration(nameof(@BaseMapper .MapAudit))]
  [IncludeMappingConfiguration(nameof(@BaseMapper .MapOwnable))]
  public static partial HouseDto ToDto(this House house);
}

// Same for Form