You have a number of options as far as I see it.
1 - place a sight bob/bung/big dry fly at the end of your tippet and then 5' - 7' down tie on your buzzer or a team of buzzers. Remember, your line does not lie straight down from the indicator as it lies at an angle so you need to tie it on a longer line to get down to your required depth
2 - have a long leader with a team of buzzers (say 2 - 3 or even 1 if that is your preference) and then, at the end of your leader, tie on a booby or big dry fly. Your buzzers will then sink under the surface and will be supported either end by your floating line and bouyant fly. This is called the 'Washing Line' method.
3 - Use flurocarbon to sink your buzzers quicker and then retrieve them slight quicker quickly after they have landed - your buzzers will likely be in the 4' region under the surface.
4 - Try a Neutral Density line wich is, in effect, a very slow sinker. Begin retrieving soon after the flies have landed and, again, you will likely be in the top 5' of water. This method also works well with the Washing Line method as above. The Pirate sells a great Neutral Density line for less than half the price of the 'usual suspects'
5 - Try an Intermediate line or Di3 and the washing line method with a slow retrieve and you will, again, be in teh top 5-2' of water.
Have fun and hold tight for some thudding takes
Ben