Billboards servicing different roadways

I’m in the process of applying for a permit for a billboard that would service a major interstate Highway. However, there is an issue regarding the minimum space between another billboard. The other billboard does not service the interstate though, it services a different road. My question is the following, does the minimum spacing allowed between billboards in the local zoning code apply to billboards even if they don’t service the same roadways and neither can be seen from the other roadway? Thank you for your attention on this matter.