This David Haas song is a song of unity that I could see as an opening song, although it has many liturgical uses. The work has its inspiration in the community depicted in Acts but is a prayer for every parish gathering.
There are eight verses so I would be choosing the most appropriate, but Haas spoke about using the whole song for entrance even if broken up in amongst the entrance rites.
GIA sell the sheet music here and the text is in their preview.
This is the quality of song that we should be considering introducing to our assemblies. Clare Johnson, in her main presentation at the APMN conference spoke of songs being “sticky but not tacky”. I think this would stick.