Set element closeness measure

Apologies if you saw this on php-general already... Give about 1 MILLION sets of 1 to ~20 integers such as: (15, 42, 57, 314, 1024) I need to be able to compare any two sets and determine if any of their elements are within, say, 20 of each other. Example: (10, 100, 1000) CLOSETO (50, 150, 1050) ==> FALSE (10, 100, 1000) CLOSETO (15, 150, 1050) ==> TRUE [abs(15 - 10) < 20] (10, 100, 1000) CLOSETO (115, 1050) ==> TRUE [abs(115 - 110) < 20] The sets are actually ordered sets, monotonicly increasing, if that helps. Each set has another 36 bytes of associated data, of which 32 (two int4) can be composed for a unique ID. Or I could just assign an ID to each one. I could, of course, create a table of about 10 MILLION rows and be searching through that... But my gut says there should be an easier way. I've look at the ~/contrib/array and even considered converting each set to a built-in "path" datatype -- But neither of those seems to provide a "any_vertex_near" function for comparing two objects. Any ideas?...