The capsule is formulated for extended release by containing the drug as a group of beads that have different coatings of different thickness. As you may expect, beads with thinner coating will dissolve earlier to release the drug for absorption than those with thicker coating.
What is important is that not all beads are the same. And you cannot tell which beads have thick coating and which ones have thin one when you separate the dose. Therefore, if you have include the thin coated beads into a dose, the drug will be released and absorbed quickly, which may lead to excessively high plasma drug concentration. However, if you include the thick coated beads into a dose, it takes very long for drug release & absorption, and you can't get the therapeutic benefits within a reasonable time period.
Therefore, it is dangerous to separate the dose into three. If you really wanna try on this drug, you may ask the doctor to put you on a lower dose since the capsule comes in a number of strengths lower than 30mg.
Hope this can help.