You can do this using dropdown menus and loading them with lists. Use HTML and the onchange event to run a command. Here is a quick example, I would add some (Select) or some kind of blank option as the first option so that when it changes to that the models don't switch this will help when it loads up.
ui html panel("Phone: <select variable=\"#selectedPhone\" list=\"#phones\" list-fillwith=\"options\" onchange=\"ubot.runScript(\'ChangePhone\');\"></select>
Model: <select variable=\"#selectedModel\" list=\"#models\" list-fillwith=\"options\"></select>",300)
add list