Could be possible, I've done similar under SQF. I worked for a food sterilizer, small family run business that occupied a part of a warehouse suite. The SQF certified food handling side made up about 1/3 of the total suite, separated by a walled partition with a chain link gate from a separate business owned by the same people that stored all sorts of random logistics items. I'm talking pool chemicals, combustible stuff used to make fire starters, adult toys, kid toys, etc. We drew up a map that laid out the entire suite, showing which portions were outside of scope, and all relevant SOP's made reference to never allowing comingling or transport of items from one business into the other. We did have to use the same dock doors for both businesses, but our receiving/shipping SOP's forbid loading separate business trucks at the same time (and easy to enforce since we only had one forklift). The auditors always inspected the opposing side for potential risks: pest control still applied to the doors, as did building security for our food defense, and so on. We always had great chats about the types of merchandise stored there. There was even food on occasion, usually ambient pre-packaged snacks like chips or whatnot, but none of it was ever related to the sterilization business.
I think the big key here was it being a totally separate business. Additionally, I'm 100% positive we would've receive a critical failure if they ever found food product from the sterilizer stored there or obviously the general merch stored on our food side. But our programs were solid, and it was a really easy business to run and keep separated.
To attempt it where you're describing, I would imagine needing totally separate staff for all production and sanitation work. Your SOP's would need to heavily document the difference between the areas and processes. Ideally it should be done under a separate business name as well to avoid the impression that you're trying to pass off the production under your SQF cert. "Hey, we're SQF certified and also handle these things, wink wink" isn't a good look, and it'll be really easy for your clients to feel misled that you're SQF certified as they purchase these allergens from you. The biggest and most important takeaway I had from your post is that you're a Peanut Free Facility: Well, even if you partition it out and do a separate business name, you won't be a Peanut Free Facility anymore, and customers will feel misled when they show up in person and see the backroom operation.