osmobts multiple bts

Hi, I have followed the steps as in Multi-BTS with Osmocom and a single UmTRX <http://umtrx.org/multi-bts-with-osmocom-and-a-single-umtrx/> but I wasn't able to get the right results. I was able to get both TX transmitting the broadcast channel but when I try to connect my phone, only BTS0 works fine. When I try to change the BTS unit_id, I noticed that only the BTS having the lower unit_id would work while the other one only transmits broadcast signals (ex: unit_id 1801 works if I have 1801 and 1802). Any ideas what could be the problem ? Thank you, <http://umtrx.org/multi-bts-with-osmocom-and-a-single-umtrx/>