Collect contact details using re-identifiable link

Hi All,

I am building a survey that is anonymously collecting (_potentially_ commercially sensitive) information about a respondent's organisation, and then want them to be able to opt into being involved in a deeper research case study, which would then (and only then) require them to enter organisational and contact details. But for those that opt in, I need to link the survey responses to the contact details, so cannot redirect them to another external site where they enter unlinked contact info. Does Qualtrics have a technical workaround for being able to effectively store the contact details in a separate database (say, in another Qualtrics survey) but which retains some kind of personalised respondent code that acts like a pseudonym? That way the survey would still be anonymous.

Thanks! Ed