It's interesting how these well intentioned ethics regulations can impede relationship building. Because you can't do this you don't get the regular updates with the client and potentially more business.
The key is that you should not exchange company resources for what may be perceived as or actually be personal benefit. Outside a contractual term, set up a quarterly dinner to strategize, synchronize, assess, etc where the vendor pays? Sure! But, explicitly concede a material business term in a contract in direct exchange for a term that personally enriches you? No!