InfoPath Dev

I have a situation where we have 90 clients that we send invoices to. All other clients (about 80) have to pre-pay. I need to have a rule where depending on the client number, an option appears giving the user the option of sending an invoice, but only for the 90 clients who have that option. For the remaining 80 clients, that option should not be available. Is there an easy way to do this that doesn't involve creating 90 rules, 1 for each client? Thanks, K13

Could you create two sections, one for the 80 clients and one for the other 10?

The problem is: how do you know which client numbers belong to the 80 and which belong to the 10? It probably doesn't make sense to hard code this into the form.