Adding simple conditions to terms (or other places)

I have created a custom field "payment method" for clients, which can either be debit or bank transfer. Depending on the content of this field, I'd like to display different terms on the invoice. If the content is "debit", I'd like to show "the money will be transferred automatically" (which is only an example of course ;-)), if not, it should be another text.

I found out that I can display the content of the field by putting into the general terms fields. But I would like to use some simple conditions there like .

Is this possible?