Retirement Dinner Invitations

Dear Limo Princess,
I am putting together a surprise retirement party for a physician at a rather pricey restaurant. I would like to convey to individuals they are responsible for their own cocktails and dinner. Do I put this information in the invitation, if so how do I word this without sounding rude.

Dear Michele,
If you are sending invitations then it will be assumed that you are also picking up the tab for the dinner since invited guests are exactly that--guests.The proper way to do this is to telephone the people that you wish to attend and tell them group members are all meeting at the restaurant for dinner and Dr. Smith is attending and is unaware that people will be gathering there to wish him well in retirement and that you hope they will be able to join the celebration and that you have made arrangements at the restaurant for a group of people with separate checks. Then you ask if they will be able to attend as the restaurant will need a head count.It's not a retirement party unless the medical group/hospital or whomever is picking up the bill for the event.