LIsting Submission – Data Handling

I have been reading about listing limits and that there is only one listing submission page allowed. I am using the Responsive Directory theme and here is my dilema. I want to have different data field that apply to different listing categories. I can add all of the data field and have one long form on the listing submission page and then the lister would only fill out the appropriate field or if there is a way I can use conditional logic based on the category then only the correct field would appear. I have created a child theme so I could create a custom listing submission page; however, I need a little help or advice. Is this possible and if so can anyone sugget the few lines of php I would need?

The other option is to use a plugin like grafity forms which has this feature built in pluss a couple of other features I would like to use. If I werre to use gravity and embed the form in the page how do I handle the data and directing it to the correct database and fields?

Or is there another option? Thanks for all the help and advice in advance!