Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
rĕgĭōnātim, adv. [regio], by districts or wards: regionatim commerciis interruptis, Liv. 45, 30, 1; 40, 51 fin.: (edidit) ludos regionatim Urbe totā, Suet. Caes. 39.