Add 2 true/false parameters to your user collection.
1 called “Business Owner”
1 called “Customer”
Set those to check automatically on the signup forms for said users to specify who is a business owner and who is a customer.
Create a collection of “Businesses” with a one-to-many relationship to users where a user can have many businesses but businesses can only be owned by 1 user. Rename the parameter in the user collection to “user businesses”.
Add a many-to-many relationship with users and businesses and rename both of the parameters. In the business collection, rename this new user parameter to “Customers” and then rename the user collection business parameter to “Customer businesses”
On the screen where you want the business owners to see their business, add a list of businesses and set it to “logged-in user > businesses” and set the visibility of this list to only visible when “logged-in user > business owner > is equal to > true”
On the screen where you want to send push notifications, add an input and a button. Set the action on the button to trigger notification to “All Users” and add a filter where “Logged-in user > Businesses > Customer Businesses > All” to send push notifications to only customers of the businesses that are owned by logged-in user.