How can we randomize multiple rosters with an equal probability of appearing?

Dear all,

I generate 22 rosters (fixed set of items) which represent 22 blocks of the choice set. Each roster contains 2 questions, one is numeric and the rest is single selection, and 4 static texts with 4 JPG attachments.
I would like to randomize 22 rosters with an equal probability of appearing in the questionnaire.
Thank you very for your help.
Best,
NhuMan