I don't know the title of the song, but we sing this song 99% of the time for visitors. We play it in F, Reggae style:
"You are welcome in the name of the Lord *2,
For we see in you, the glory of the Lord,
You are welcome in the name of the Lord...
[repeat]
Happy to bear, happy to share,
our burdens with one another that's why we are here"
the other 1% is:
"Let There Be Love Shared Amongst Us"...
Unfortunately the other one that's very popular in my native language wouldn't make sense to your visitors, but the translated lyrics are:
"You have done well by coming,
whilst we are in the presence of the Lord,
to hear His voice"
[repeat as many times as you wish...find a suitable tune to go with lyrics or tweak them...something reggae or shuffle style like...]