Redirect before end of survey

Hi guys!

Having some issues with my survey (I am terrible with technology).

Basically,

Participants complete some of the Qualtrics survey
Complete some inquisit tasks on on a different site
Come back and answer some more of the Qualtrics survey

I am able to redirect participants to Inqusit site at the end of the survey, but how do I re-direct them mid-survey? (Note: only some participants will be re-directed as they need to consent and download a web application?

Thanks!