Invitation for obtaining a Visa

Hello,

I intend to travel in a group (3 people) in several cities around Beijing. Our company wants to send us to contact some potential suppliers in China, however the Chinese counterparties are not very quick to issue us an invitation (which we need it in order to apply for a Visa at the Chinese Embassy here).

We decided then to come as tourists, however we still need an invitation (and of course the booking for hotel and airplane tickets, too). What do you suggest to us ? To call a hotel in China and to ask them to send us an invitation ? We are not sure about the duration of our stay, because we don't travel as tourists, but in some kind of business purpose, for several days only, so maybe even we don't stay in each location one full day.

Thank you.