golf foursome random selector

I am match captain for a golf league which entails providing from a membership of 70 odd players a list of foursomes randomly chosen. I have tried several of the solutions in the random list thread and have been able to get some of them to work. I attach an example of what I currently use. There are two features that would be nice to have.
1) it would be nice to have a start/stop button so that the randomization does not run until I want it to and stops after I have the list randomized. I have tried disabling macros and setting security level very high but in both cases I get randomization when I don't want it.
2) It would be nice to arbitrarily select the list length since varying numbers of golfers show up to golf every week. I tried one of the programs that claimed to let me set number of choices and list length but it did not work. What I do now is edit the program I have to various lengths, or have several programs for differing numbers of players

I would try either an IF statement to a cell that is not being used. Cell f1 could be =IF($F$1="","",what ever formula you have in there rank or rand(). your rand() try RAND()INT(*cell#+1) then countif your names column to populate the random number it will generate from. the INT just gives you an integer whole # no decimal. match your names into the foursome field and done. as for not randomizing each time turn off the auto calc function in your options then when ready to randomize push F9

I am having a little trouble making your suggestions work. Could you modify my sample spreadsheet to work with your system.

this is very similar to yours sorry I was mistaken with the if statement. you will have to copy and paste values to another sheet to retain your random orders