This study investigates the impact of co-channel interference caused by external terminals on multi-user bi-directional amplify-and-forward based wireless relaying network. The investigation considers multi-user pair and a single bi-directional relay terminal and a finite number of co-channel interference in the system model. A lower bound on the end-to-end outage probability is derived for the simultaneous transmission and the opportunistic source-pair selection strategy. According to analytical, asymptotic, and Monte-Carlo based computer simulation results, the opportunistic source-pair selection strategy achieves a near-optimal performance for the inter-cell interference caused by other user-pairs within the system. Results also show that the opportunistic source-pair selection strategy also achieves optimal diversity order, which is equal to N, in high signal-to-noise ratio regimes. Results also show that the co-channel interference degrades the achievable diversity order from N to 0 while also affecting the system coding gain.