Air carrier departure from FLO; prior to Tower opening; expressed frustration regarding IFR release procedures that sometimes result in an aircraft at the gate being released prior to an aircraft number one at the runway.

Narrative

On the morning of Feb/XA/09; at approximately XA35EST; our flight taxied out for takeoff in Florence; SC. The weather conditions were favoring a departure off of Runway 9. Upon arriving at the hold short of the runway point on the taxiway; I set the parking brake. Florence has trouble with 2-way radio communications from ZJX; so they set up a telephone number to call in on to get IFR clearances. On the morning of Feb/XA/09; Aircraft X taxied out to Runway 9 in Florence. Upon reaching the hold short line of the runway; I called the provided number to FSS which 'relays' clearances for Centers. I was told that it would be a little while because Carrier Y had already called for their clearance. The Carrier Y flight they were referring to Carrier Y that was still sitting at the gate that had called for their clearance and now had blocked off the airspace for departure. This procedure is not acceptable; the Carrier Y flight departs at XA42; while we depart at XA40. The 2 days in a row that we were in Florence; we Flight X were at the runway ready for departure while the Carrier Y flight was still at the gate. I do not know what Carrier Y's procedures are about cell phone use in the flight deck for operational needs while the aircraft is not moving but away from the gate; but common courtesy and professionalism would dictate that you don't block the airspace for yourself when someone else needs to depart prior to you. Some suggestions: Have the Tower open 1 hour earlier. Install an RCO for ZJX in FLO. We were actually able to contact ZJX using our #1 Communication and get them to release us with visual separation; but this situation is not conducive to smooth and reliable operations.