I would not not assume that the DSL modems will live in the enclosure. The stations may have their own modems packaged with, or built in to their equipment, in which case they would need the raw DSL circuit. They may also want POTS.

I would put in 4 RJ11 jacks, cross connected back to the demarc, and labeled with the box/jack numbers.

A lot of times the radio folks use POTS or ISDN-BRI.