Only thing to be careful of if I understand the requirement right is that you need the same type of transaction printed on a different printer based upon customer type. When you do what Mihir suggested, you want to make sure you only have the receipt types defined for each receipt format you want.
We run something like this. We have 2 printers defined, the 40-col one for printer 1 and a laser on printer 2. In the receipt format for printer 1 we have a template entered for "Sales, Payment, Pay Out, Cash Drop, and Report". In the format for printer 2 we have templates entered for "Layaway, Quote, and Work Order". This way we don't have two of the same type of transactions printing on both printers. If you do need this, you will have to set one of the printers to "Print receipts only after asking the cashier" as part of the properties in defining that printer in the "Register Properties".