How can I have a fixed custom search filter on top of the global search?

radisb

I have a simple table on which I want to use the global search but I also have somewhere outside it a checkbox that when checked it will apply a custom row filtering (specificaly it will filter out the rows that have null in a specific column) on top of the global search filter. I thought I had 2 options, but I am having problems with both of them:

1. Use column.search, but I cant find how to trigger it on top of the global search whenever someone uses the global search
2. Use $.fn.dataTable.ext.search but this is applied to all tables, and I have other tables on my page, which I dont want to apply this to.

Any ideas?

Thank you in advance.