Thanks so much for your replies, Bill and Scott! I am going to attempt the suggestion of Scott(using the Control track), but I suspect that Bill's comment may well be what has to be done. Nonetheless, Thanks to each of you for taking the time to repsond; I do indeed appreciate everything you always have to offer us amateurs when we present a seemingly insurmountable problem!

Very special personal regards to you both, Bill and Scott, extra-special friends and colleagues, who never fail to come up with some sort of solution!

TED