Can I build my own GMR satellite/base station and core network based on open source software (e.g. Osmo-bts) and SDR?

Dear Osmocom community, I noticed that the OSMOGMR project is mainly about receiving and decoding downlink GMR data. Can I build my own GMR satellite/base station and core network based on open-source software (e.g. osmo-bts) and SDR? GMR is mentioned in the Osmo-bts user manual, but it doesn't say if it is implemented and how to configure it. If Osmo-bts doesn't work, is there any other project to build my own GMR base station and establish a connection with a GMR device? Best regards, Wei