Invite Question - Need help with reception card...

I some how want to let my guests know that I am having a Viennese Hour at my wedding. I want to include it on the reception card of my invitation. I just want them to be prepared that my wedding is 6 hours - 7:30pm - 1:30am but I DO NOT want to include the times.

Anyone ever see this done before?

Any suggestions?

I know i have seen alot of reception cards say
Please join us for cocktails at x time Reception to follow
Name of reception hall.

You can put
Reception
Time
Name of Hall
Town, NY


Viennese Hour to follow