Write an iPhone application Navigation for delivery's

My projecjt is for little navigation for people ho work with many adress so they can put not only 1 navigate and then you need to start again to the 2 adress, so you can put 1 then second,third,fourt and up to 20-50-60-100 adress in one time....so they can drive give the packed and go for the next one wihtout touching the app everytime....Googlemaps have this on the PC version but its only to 7 addreess.....My idea is you can put them in order that you want to drive it 1-2-3-4-end or you just put this points and let you navigation decide witch one you have to do it 1 , or 3 options if you have 1 delivery with priority before 12clock so she drive you to there first and then the rest of you Points. I think is gonna be a rly handfull for guys like me in a new country ho want to start work without knowing the City will safe you 4-5 min at every stop if you doing this before you start the work like 5 min to fill 20-30-40 adress.