Yes. You can have multiple AffiniPay or Stripe ePayments accounts in Core and choose one of them as the default account for online payments. This can be done in Global Settings > ePayments, say multiple credit card or ACH transfer accounts. You can also choose multiple online payment accounts and options at the client, project or invoice level, but the payment service should not be the same. Also, whichever payment platform you choose initially, Stripe or AfiniPay, you can create more payment profiles for that account only. Check the Core Help for details.