My friend Chris is most correct here about using a pre-built RJ11 5 port splitter (+5 "C"). It's use is to give you 5 jacks with the same line/ext. (from 1 RJ11) whereas I'm guessing you actually want 5 separate lines for the 5 fax machines.
The best you could probably achieve here is 4 separate fax lines depending on the actual wiring that exists in the wall jack. In most cases you will have either a CAT3, CAT5 or CAT6 cable connected to the classroom wall jack running back to the local cross-connect room/closet etc. Any of the above mentioned cables will have 4 pairs of wires (blue, orange, green, brown) and you would need to leverage each of these to support 1 fax line each. So you would need a multi-port wall jack (commonly available) where the cable is split out so that the blue pair is used for fax line 1 on jack 1, the orange pair for fax line 2 on jack 2, the green pair for fax line 3 on jack 3 and the brown pair for fax line 4 on jack 4.
Back at the VG224 patch location you just need to match up the pair color to line # config you set up at the classroom wall jack (blue pair fax 1, orange pair fax 2, green pair fax 3 & brown pair fax 4.
I hope this makes sense...the picture below illustrates the pair color to jack # I described.