Contactor terminal numbering is normally universal, 1 switches 2, 3 to 4, 5 to 6 etc..A1 and A2 are switched live and neutral That you use for opening or closing the contactor. As for 1,2,3,4 It all depends on which brand of contactor it is as to where they are and what they do but generall if you apply power to a1 and a2 you will be able to use your tester to find out which terminals are linked
This is exactly what I'm trying to doAre you wanting to use this contactor to sort of cascade and thereby reduce the inrush currents so the mcb does not trip?