Workarounds for auto-flow 'review form content pushes to password protected pages based on areaID/tag'?

Feeling new love for SqSp. Few sites in.

Any good workarounds to get a simple flow where a visiting user can;

...use a public/simple form to review a local service (area ID dropdown, score metric, free text comment) then 'on submit' posts to a password protected message board, based on area ID? Allowing local service provider(s) to see only their feed of comments.

Could use a 2-step form where first area ID screener pushes to 'local form' page then a direct 1:1 between form submission pushed to a regional results page. Serving free text form content as blog-style posts back into SqSp is prob the exam question here?

I can fudge a manual workaround for mvp. Would be nice if SqSp could get me to test without dev spend. 

This community seems to have the ninja moves to solve lots of edge-case needs. Hopeful. 

Good vibes all.