Hi all, I know that

const generalPreferencesUrl = url.resolveTaskLink('ADMI_GENERAL');

will give me the General Preferences page, but what's the trick to get it to also select the 'Custom Preferences' sublist?

what do you mean by "select"? if it is just getting the values, I believe these should be accessible globally via

runtime.getCurrentScript().getParameter({name : 'custscript_name'})

regardless which script you are calling from

I don't think selecting the sublist in the UI is possible without a client side script which you wouldn't have on that page. If NetSuite had done tabs instead on the page you could uses selectedtab in the url parameters.