my script will crash every time when one of the blocks is destroyed or missing

my script will crash every time when one of the blocks is destroyed or missing
i am looking for another way
i do it this way now:

void Main(string argument)
{
IMyTimerBlock Tsaver = GridTerminalSystem.GetBlockWithName(itemname+"T [saver]") as IMyTimerBlock;
IMyTimerBlock Ttwo = GridTerminalSystem.GetBlockWithName(itemname+"T [two]") as IMyTimerBlock;
IMyTimerBlock Tfp = GridTerminalSystem.GetBlockWithName(itemname+"T [Floor plan]") as IMyTimerBlock;
IMyTimerBlock Tup =...

my script will crash every time when one of the blocks is destroyed or missing