Hi Rony,
This gives me an idea that instead of rewiring the lines through the splitter, if we could add extra splitters at every phone point, then this should do the same job. Are these splitters available seperately or do they come with the modem only? Another option would be to copy the filter circuit. As I have only one working set, I don't have the heart to open it and tinker around but my guess is that it is a simple capacitor and inductor circuit. A series low impedence inductor with the phone output will allow low frequencey phone signals to pass and offer high resistance to the high freq. adsl signals. A low capacitance series capacitor with the adsl output will allow high freq. adsl sigs. but block the low freq. phone signals.
So if we can get the value of the series inductance for the phone output, we can buy it from the market and connect it in series with all the parallel phones and thus avoid rewiring. JTD and some others have dabbled with the adsl so they could give some tips. :)
Check out this link for a filter circuit, it may be of some help. http://www.epanorama.net/documents/telecom/adsl_filter.html.
Regards, Rajesh