Thank you pringletech,
I chose to use MANY conditional rules. Not ideal, but it does work out the box. I still have a lot to learn about coding. Making the manual method the best for right now.
I started by using this website to identify all the zip codes within a 25 mile range of my locations.
Find ZIP Codes Inside a Radius (freemaptools.com)
I then created a table in excel. With all my stores as the headers and zip codes within 25 miles of them. Then I created arrays of site combinations. Example = store 1,2,3,4,5 - 1,2,3,4 - 1,3,5 - 1 - 1,2, - etc… This is important to not forget any combinination to see if the group shares a zip code.
Using filters in Excel I was able to identify what zip codes the arrays shared. I did so by filtering out blanks for sites within the chosen array (i.e. 1,2,3,4)
I then created form fields with conditional logic to display if any rules matched. Each array got its own form field. I chose SHOW if ANY rules matched. The rules were ‘zip code’ IS XXXXX. XXXXX being the zip code. This was about an hours worth of data entry work. Creating 100s of conditional rules for the user’s browser to calculate per the Gravity docs - my computer it runs quick.
I also had to create a form field that had EVERY zip code used in the other form fields. This way if the user typed a zip code outside our service area, they would get a message.
This took me all day today and wasn’t ideal, but it did get the job done for now. Right now we just have 6 locations but on track to add 80+ this year. This manual process isn’t scalable and will likely be seeking a developer to build this function out - stay tuned.
I hope this helps Erica