you can keep tangs with triggers , without any problem... adding the tangs all together (as adding tangs slowly will make too hard to handle their own agressiveness..., choose fast and bold species as clown tang, hippo , sailfin, yellow etc) ... and add triggers of different sizes , and make some rock arrangements to creat some kind of shelter to them... your tank space would be fine for some species as , clown , ****** , picasso, blue jaw... I would not try undulatus , queen, blueline and titan due excessive agressive behavior... don't forget to protect any powerhead or heater cord with some plastic grid or net to prevent any problem due a trigger bit... In my 60 gal tank , I keep a clown trigger (4 inch) a ****** (1 inch) , clown tang (1 inch) , hippo tang (4 inch) , red sea sailfin(4 inch) , mac's angel (4 inch) , a betta marine (2 inches)and 2 neon goby... and the less agressive fishes in this tanks are the triggers...angels and tangs feeds much more agressive way (spilling water) so a trigger comunity with proper shelter would be fine for you... tangs will help triggers to do not fight with each other...