GMT Offset based on Campaign

HI everyone im facing an issue that many leads are with different area codes out of state and get out leads on the hopper several times a day. The leads are moving to state with different area codes, it happens a lot how can i set the GMT Offset based on Campaign location ? not based on the area code of the number ?? i've found a temp fix and made an update to the database
.UPDATE `vicidial_list` SET `gmt_offset_now` = '-5.00'