Get selected items from multiple lists with multiple checkboxes

Question

In my screen, I have two sets of lists. List 1 has 5 checkboxes (ex. Id's 1,2,3,4,5). List 2 has 6 checkboxes (ex. Id's 1,2,13,14,15,20). These 2 small lists are never going to have too many records (not going to need pagination).

My problem is that all my previous examples had only one list, and I can get the list of the ID's of the selected checkboxes for ONE list. This time though, I need to have the values of the selected checkboxes somehow in 2 arrays when clicking a Submit button.

Can anyone point me into the right direction, how can I do this? thank you!