NOOOOO!!! This is not true of those in question. Please do not suggest this, as I have been asked this question before, and no doubt people have tried it. It will not work for brittlestars! And it may not work for many species we keep (they are not healthy enough it many situation). For some, yes, it may work. But not for the animals in question! This is my worst nightmare!
What do you want to know about brittlestars? Killafins is correct, tell us about your tank size, age, water params, inhabitants, etc. This will help figure some things out! Keeping two, BTW, is not a problem unless you don't have much LR. And I do suggest that they are spot fed, unless in a tank with large fish where there is a lot of food in the system.