Juice add on to restaurant / hotel menu

I have some questions in regards to consulting / partnering up with restaurants in the area who want our cold pressed juice and want to showcase it on a separate menu within their brunch program. How can I work around that? Does there need to be an official operating agreement?
I currently work out of One location that has allowed me to designate a kitchen space as our production space… certified by the board of health. The other restaurant I do not make the juice there but will provide it. The set up will look like this: small cardstock given along with a brunch menu with our logo and 2-3 juices available. Growler form poured into 8oz glassware?

Technically not wholesaling but the product would then be purchased through their POS system and then paid out to me as a consulting or partnering amount?

Not sure if this makes sense, let me know all thoughts! Much appreciated.