I have done 1 filter for all phones equipment as follows:
at the demarkation jack I installed a splitter , on 1 side of the splitter I plugged in the filter(regular filter that comes with kit) and into that I pugged in the telephone line, so now all jacks are filtered with 1 filter.On the other jack of the splitter(unfiltered), I installed the modem with the cable supplied in the kit. from the modem to the router and then out to the cat5 cables to my computer.You can run another line for the modem, but Bell recomends not using the flat extension cables, rather proper twisted pair phone wiring, available at hardware stores, Home depot etc.
I had a tech guy here doing a line repair and he said that was a nice setup.
Note,,, when calling for tech support I remove the router & filter, unplu all phones except for one and install the filter on that phone, with the modem beside me, Tech is very likely going to ask what lights are lit etc, so having the modem in eyesight is handy, plus they won't support you if you have a router attatched without paying the $80 router suport fee.
a site with some interesting options for DSL filters
http://www.excelsus-tech.com/index.cfm?fuseaction=products.Category&id=2