If you do that, you won't be any further ahead. You still have to select the bits that you want to erase.
It sounds like you may not know the various ways to select that will make things easier. For instance if you orbit your view so that the bits you want to chop off are all facing towards the right of your workspace, you can drag out a Right to left selection window over the geometry that you want to get rid of. Stop your selection window just short of the cut lines. That will select all items even partially within the window. Once selected, just hit the "delete" key. To select only those items that are edge to edge or endpoint to endpoint completely within the selection window, do a left to right selection.
To select a surface and it's bounding edges, double click on the surface. To select all attached geometry "triple click
on the surface. ( can't use this above becuse the cut line is still shared by the other portion of the model so it is still "attached") Lot's more ways to select also.
You are doing a bunch of advanced stuff but I think you may be missing some of the basics that may make life a lot easier for you. Groups and components definitely being a biggie.
If you could post your model, and just explain what you would like to accomplish, ( multi-part group??? do it over and over again???) Maybe we can provide some input on how to accomplish faster and easier, yes?