stops at layer changes

As the hedding may suggest, what i am after is, when in sheetcam you setup a layer, once that layer is completed will Mach3 stop and require the start button to be pressed. I will word it differently, I have not taken as much notice as probably I should have. What I am trying to achive is this. I will be using the routing function of my plasma machine (have done it before and has worked quite well). What I need to do is route one layer with a specific tool, once that layer is completed, change tools, reset the top of the material to suite the new tool and complete the next layer. Having the process stop for the tool (milling cutter) is crutial. I have already set up the layers in sheetcam and have done the simulations and all seems fine. I have never tried tool changes before so hense why I am asking. I am hoping that this process is quite simple and I am worring for nothing. Any help would be appreciated. Thanks in advance