I have this data set: ID HOH 903 1 AB4 0 26A 0 E52 1 53D 0 40 0 7B6 0 E8D 1 A80 0 AA6 0 63A 1 3DB 0 A57 0 D27 0 450 0 F4D 0 0A2 0 37F 1 E52 1 282 1 268 1   The IDs are individuals and HOH = 1 is the head of household for the next records with HOH = 0.  Then the next HOH = 1 start the next household group.  I need to group those like this:   ID HOH Household 903 1 903 AB4 0 903 26A 0 903 E52 1 E52 53D 0 E52 40 0 E52 7B6 0 E52 E8D 1 E8D A80 0 E8D AA6 0 E8D 63A 1 63A 3DB 0 63A A57 0 63A D27 0 63A 450 0 63A F4D 0 63A 0A2 0 63A 37F 1 37F E52 1 E52 282 1 282 268 1 268   So create groups where groups do not exist.  The file comes sorted so the first HOH = 1 and HOHs = 0 are in the same household.   Thanks ... View more