I have 2 categories of products that take up to 7 days to ship out because they are custom made (specially roasted coffee). Although it's pointed out on the product page itself that it takes that long, I would like to add a pop up "reminder" box at checkout if a customer orders something from that category.

So, for example, if they order the special roast coffee and have it in their cart, I would like for a box to pop up during checkout that says something like "You have added a product to your cart that takes up to 7 days to ship" and then have an "okay" button you would push to close (or click the "x" in the corner).

Is this possible?