Yes, if you are using FileMaker 10 or newer.
The OnObjectSave (Dropdown) or OnObjectModify (Popup) trigger can be used to perform one fo the following two scripts:
Go to Layout [YourTable::YourDropDownField]
If [ yourTable::yourDropDownField = "A" ]
Go to Layout ["Layout A"(tableName)]
Else IF [YourTable::yourDropDownFIeld = "B"]
Go to Layout ["Layout B" (tableName)]
and so forth....
The first script uses the "go to layout name by calculation" option and the names in your value list must exactly match the names of your layouts. The second option does not require this exact match in layout names.