Stove Burner Issue

Thanks all. Sorry I forgot to say, but as some of you surmised, it is a propane stove. Yes, two back burners are on-off and front (the large one) is adjustable. Checks with what the manual says, but my gosh! it would seem so easy for the mfr to make them all adjustable.

I guess my question is whether or not I could simply replace the back burners with adjustable ones.

I guess I can contact the mfr, but I have often found this resourceful bunch can come up with solutions which seem to elude the manufacturer!