Buter,
I changed my mind. What you describe is common. I've owned 2 LP's and 2 335's, but the last one was about 15 years ago, so my memory was mistaken.
As a matter of fact, I never liked having separate volume controls. On my last LP I modified it to have a master volume, 2 pickup volumes that didn't go all the way to zero (grounds lifted), and a single tone. There is a circuit like that on Tim's link.
On the guitars we build now, there is usually just a single volume control, with or without a tone pot, sometimes a blend control.
If you want to change your guitar, use one of the circuits on Tim's link that says "With Independent Volume Controls". The main difference is the pickup goes in to the center lug, and out from the end lug.