I think what you want isn't supported today in the designer itself, but you can achieve it with a simple .cmd file on the command line and use the cligenerator. The cligenerator is the commandline code generator we have and you can generate 1 project + preset at a time, but you can configure everything on the commandline, so you can create a .cmd file which calls the cligenerator twice: once for the first preset and once for the second preset. See: https://www.llblgen.com/Documentation/5.5/Designer/Functionality%20Reference/CliGenerator.htm for details about its usage.
We use the cligenerator ourselves to generate the code for our unit tests for instance using various cmd files. This is the main .cmd file we use:
@Echo off
set designerBin="\Myprojects\VS.NET Projects\LLBLGen Pro v5.5\Designer\Gui\bin\Debug"
set destinationRoot="\Myprojects\VS.NET Projects\LLBLGen Pro v5.5\UnitTests\LLBLGen Pro\LowLevelAPI"
set destinationAdvancedRoot="\Myprojects\VS.NET Projects\LLBLGen Pro v5.5\UnitTests\LLBLGen Pro\AdvancedQueryAPIs"
pushd.
Call "AdvancedQueryApis\LLBLGenPro Projects\GenerateCS.cmd" %designerBin% %destinationAdvancedRoot%
popd
....
Then, the GenerateCS.cmd file looks like:
@Echo off
cd %1
Echo ================================================================
Echo Generating code: Adapter, C#, Regular models.
Echo ================================================================
cligenerator "%~2\LLBLGenPro Projects\Northwind26.llblgenproj" "NW26.Adapter" "C#" ".NET Standard 2.0" "Adapter" "SD.Presets.Adapter.General.Netstandard" "%~2\AdapterDAL" 0 "%~2\LLBLGenPro Projects\log_NW26_Adapter.txt"
Echo ================================================================
cligenerator "%~2\LLBLGenPro Projects\Northwind26.llblgenproj" "NW26Async.Adapter" "C#" ".NET Standard 2.0" "Adapter" "SD.Presets.Adapter.General.Netstandard" "%~2\AdapterDALAsync" 0 "%~2\LLBLGenPro Projects\log_NW26_Adapter_Async.txt"
Echo ================================================================
cligenerator "%~2\LLBLGenPro Projects\InheritanceTwo.llblgenproj" "InheritanceTwo.Adapter" "C#" ".NET Standard 2.0" "Adapter" "SD.Presets.Adapter.General.Netstandard" "%~2\AdapterIH2DAL" 0 "%~2\LLBLGenPro Projects\log_InheritanceTwo_Adapter.txt"
Echo ================================================================
cligenerator "%~2\LLBLGenPro Projects\Sql2016TemporalTableTest.llblgenproj" "Sql2016TemporalTableTest.Adapter" "C#" ".NET Standard 2.0" "Adapter" "SD.Presets.Adapter.General.Netstandard" "%~2\AdapterTemporalTableDAL" 0 "%~2\LLBLGenPro Projects\log_Sql2016TemporalTableTest_Adapter.txt"
...
This is just an example, but I'm sure you can get it working with just 2 cligenerator calls. The cligenerator is installed with the designer in the designer folder and requires a license, so make your .cmd file call the cligenerator inside the designer folder and it should be OK.
Hope this helps making things easier
btw, you don't have to close the designer to run the cligenerator. It loads the file from disk and can work with it even if the designer has the project open too.
The sourcecode of the cligenerator is in the source archive in the 'Extras' section under 'My Account' on the website, if you want to adjust it.