enum prison_Interiors{ Float:entrance_Coords[ 3 ], Float:interior_Coords[ 3 ], interior_ID, virtual_World };

static const
        prison_Positions[ NUMBER_OF_PRISON_POSITIONS ][ prison_Interiors ] = {

        {{ Entrance_X, Entrance_Y, Entrance_Z }}, {{ Exit_X, Exit_Y, Exit_Z }}, Interior, Virtual World }, // Replace   this with coordinates, and then add positions just down here. NUMBER_OF_PRISON_INTERIORS must be the amount of lines here, you know that probably.

};

// Then you can use this example very easy, like the example below

for( new i = 0; i < sizeof( prison_Positions ); ++i ) {

     if( IsPlayerInRangeOfPoint( playerid, 5.0, prison_Positions[ i ][ entrance_Coords ][ 0 ], prison_Positions[ i ][ entrance_Coords ][ 1 ], prison_Positions[ i ][ entrance_Coords ][ 2 ] )) {

          SetPlayerPos( playerid, prison_Positions[ i ][ interiors_Coords ][ 0 ], prison_Positions[ i ][ interiors_Coords ][ 1 ], prison_Positions[ i ][ interiors_Coords ][ 2 ] );
          SetPlayerInterior( playerid, interior_Positions[ i ][ interior_ID ] );
          SetPlayerVirtualWorld( playerid, interior_Positions[ i ][ virtual_World ] );

          return true;
     }
}

// This will check if the player is in the entrance coords, put him to te interior coords, set interior id and virtual world.
// And you can do the reverse process to put the player back to entrance coords