Issac, You should write your numbers to eeprom. Say first number form location 0 to 15 (assuming your phones numbers of 15 digits), the 2nd from 16 to 30 and so on.

Than you will write the start and end reference in an array byte.

Start[0]=0 ; Last[0]=15 - Start[1]=16; Last[1]=30 ..... And so on.

Than you make a loop for/next to repeat the number

For call_numb=0 to 4

Hserout "AT+CMGS="

For num = Start[call_numb] To Last[call_numb]
Read num,send
Hserout Send
Next num
.
.
Here your code till Hserin 15000, SMS.....
.
Next call_numb

It should work

Cheers

Al.