Sight-seeing Trip to China and Tibet

Hi! - I'm a Malaysian living in Johor Bahru. My daughter is Singaporean and she is going with a group (all Singaporeans) for a 10-day sight-seeing trip to China and Tibet in late April to early May 2013.
My daughter is inviting me to join the trip. However, the person organising the trip says I cannot apply for the China visa and the Tibet entry permit because I'm the only Malaysian in the group. Is this true? What documentation is required for me to join the trip so that I do not have any immigration problem during the trip? I would appreciate a prompt reply. Thank you.