Phil,
The JAMC is used for unit moves; individual pax are not normally required to transit through. It is used to chalk units and hold them, segregated from other units where required. Basically, it frees up the terminal at Nause Brighton when there are multiple ac moves happening concurrently. It also has accn available, which, GWH notwithstanding, NB does not. So, in answer to your question, a 2 hr check-in at NB should be fine when you fly to TELIC.
CH