x1 and x2 have or had (not necessarily simultaneously) the same relationship to x3, that relationship being x4, with the relevant difference(s) between x1 and x2 being x5.
The (ordered) relationship which exists/existed(/will exist?) between x1 and x3 (in that order) is the same relationship, modulo difference x5, which at some time exists/existed(/will exist?) between x2 and x3 (in that order). For differences in timing (for example: an ex-boyfriend and a current boyfriend of the same person were/are both boyfriends of that person - but not simultaneously; they are temporally-displaced co-boyfriends of that person, in a sense), mention that timing in x5. This word can be used for co-partners in romantic relationships, 'sister wives' (co-spouses) in marriage to some common third individual(s), co-parents of shared children, etc. See also: "glepanryborki'i".