What suppose to happaned if two ext make paging into one?

I try to use with paging option from two to one ext. I try it on Snom & Polycom
the result is same but strange:
1.I page from 203 to 206 the connect is established.
2.I page from 204 to 206 the connect is established too (according the 204), but no voice come from 204 to 206? why?