In a large stockpot, combine vinegar, sugar, water, canning salt, oregano and fennel seed. Bring to a boil. Add cauliflower, carrots, celery and onions; return to a boil. Remove from heat; add peppers., Carefully ladle hot mixture into 10 hot 1-pint jars, leaving 1/2- in. headspace. Add a bay leaf and 2 peppercorns to each jar; divide garlic slices among jars. Remove air bubbles and adjust headspace, if necessary, by adding more hot mixture. Wipe rims. Center lids on jars; screw on bands until fingertip tight. , Place jars into canner with simmering water, ensuring that they are completely covered with water. Bring to a boil; process for 10 minutes. Remove jars and cool.