Send Campaign to List A who are not in List B

I have 2 lists (2016 Paid Members and 2017 Paid Members) I want to send reminders to the 2016 Paid Members who haven’t paid this year (not in 2017 Paid Members list). Basically I want to exclude the 2017 Paid Members. I can’t see anything obvious. Your help would be much appreciated
Many Thanks

@TerryR See the setting for list exclude in the config_extended.php file. Copy the setting to your config.php file.

Thanks…Looked at the extended php file and got the answer I am looking for. Thanks for pointing me in the right direction. Sorted out now