Conferences and networks
Funding three of your people to fly out buys three sets of contacts. Co-hosting a workshop there builds them for a whole group — including the students.
Finding partners in Vietnam
Most enquiries to Vietnamese research groups go unanswered, and the reasons are consistent enough to fix.
Co-writing and publishing
Offering to write the manuscript because your English is better is a reasonable-sounding decision that quietly transfers control of the paper.