Step 1 - Add in User Define field with Colour column.
Step 2 - Add in below script at the end of the existing url. /ItemMaster/item/Item.aspx?Item.Colour=Red . This will help you to auto filter the asset master page.
example:http://www.autotrack.com.my/BA05B145-14A9-45B0-BAB6-0654FDE4C1EB/ItemMaster/item/Item.aspx?Item.Colour=Red
Step 3 - Add in the subMenu to your existing with you own define name
Step 4 -Now refresh your menu, you got the filter menu with Asset with Red colour only.