So it has its own cellular infrastructure, recording pings from nearby phones as they automatically seek to maintain connectivity. The result is videos like this one, uploaded by Bellingcat. Its a large stone building, constructed well before things like wireless phone signals were something to consider. One of the leaders of the group, named Stringer Bell, comes over. (Heres a YouTube playlist of some.)
The group mentioned has its own infrastructure.                                                                                                                      ]
( z0 have :ARG0 ( z1 group :ARG1-of ( z2 mention ) ) :ARG1 ( z3 infrastructure :poss z1 ) )
(z0 / have-03
    :ARG0 (z1 / group
              :ARG1-of (z2 / mention-01))
    :ARG1 (z3 / infrastructure
              :poss z1))
The group mentioned has its own infrastructure . ]
z1 :ARG1-of z2
z0 :ARG0 z1
z0 :ARG1 z3
z3 :poss z1