Thank you for clarifying that you are using the same crypto processing provider. I think it is not user-friendly. What will be your action if a user sends xrp without a tag or with the wrong tag?
You cannot retrieve it because another casino holds the same address. The user will eventually lose his funds.
I think you should talk with your provider and ask for a unique address. It's just my suggestion. If you have a better plan then you can implement it