deactivating continue button during linked online survey

I am trying to program a media lab file where part of the experiment is through an online survey provider. I would like the continue button to be deactivated while they are taking the the online portion of the survey (to prevent them from advancing without finishing the online portion). It would be ideal if I could just password protect the continue button, but that function is only available for instruction item types. Is there anything that might solve this problem?

Or, is their any way that I could use some sort of programming code to make it such that the continue key only appears when you push a certain combination of keys at the same time? Thanks!