Take an L1, L2, L1+L2 splitter, mentioned previously, and connect the Office phone jack to L1and a Linx jack to L2. Plug a 4 wire phone cable into L1+ L2.
Repeat the above using 2 Linxs.
Get 6 standard two way phone line splitters and put two at each of the first 3 phones.
Connect the plug part of a splitter to the L1+L2 jack on the first phone.
Connect the plug part of another splitter to the L3+L4 jack on the first phone.
Repeat this on the second and third phones.
Connect the 4 wire cable from the Office Linx splitter to one side of the splitter at phone 1.
Connect another 4 wire cable to the other side of the splitter at phone 1 and then connect the other end of the cable to one side of the splitter at phone 2.
Repeat the above until you have cables going to all 4 phones.
Then repeat the whole setup starting with the cable from the two Linxs to the L3+L4 splitter at the 1st phone.
Connect the L3+L4 run to all of the phones in the same manner as described for L1+L2.