Use the preset manager to make sets of the brushes you want to all load at once. In the same column that you load brushes you'll find preset manager. With that open keep clicking load in that window and add as many brushes as you want in the set. This will temporarily add them to whatever brush set you had open at the bottom of the list. Scroll down and click on the first one you want to save then while holding down the shift key click on the last one you wish to save. Click save as a set, give it a name, and save the set in your brushes folder.