Help Needed with Compex Attributes

Is there a way to set up sub-attributes? Or, text option values? Here's an example of what I need to accomplish:
Lets say a product can be engraved with either a single initial or a monogram (not both). If the customer chooses the single initial, they need to be able to enter the initial somewhere. Sames goes for the monogram. But, I don't want to set up 2 text option names because the customer will likely fill out both, & I won't know which one they actually want. There doesn't seem to be a way to create text option values.

Or, is there a way to set up the attribute, where depending on which selection they make (single initial or monogram), another set of choices appears, allowing the customer to enter the monogram or initial?
The URL below is an example of a site (not ZenCart) that does this. Add the product to the cart & the attributes will appear. Select one of the personalization options & additional choices appear:

marilynskeepsakes.cathysexpress.com/product.html?prod_id=30503

Any assistance is MUCH appreciated!

What you are asking for is known as "dependent attributes", and is not supported by stock Zen Cart (or any other general purpose free e-commerce program, as far as I know). It could be custom coded, if you are proficient with PHP and javascript.

You could make a radiobutton or dropdown attribute for initial/monogram (it is possible to require an actual choice here), and a text attribute that can take up to three (or whatever you want) letters. It would still be possible for someone to select "initial" and enter three letters, but there would not be confusion about which choice they selected - you would just have to get them to tell you the initial if they mistyped. To help thwart idiots, you could add a comment to the text attribute like "Enter 1 letter for initial, or up to 3 for monogram". Do the choices have different prices?

Thanks so much for the reply!
Yes, "dependent attributes" are exactly what I was looking to create. I'm shocked that there's not a module available for this. I have no PHP or javascript skills whatsoever, so I'd have to have to hire someone to custom code it for me. However, your suggestion would certainly be a very viable option. My products' personalization options are free of charge, so there would be no issues with different prices. Unless a "Module Fairy" appears and magically creates a module for dependent attributes, I'll most likely use your suggestion -- THANK YOU!

The problem with dependent attributes is that there are so many ways that someone could want them to work that a simple structure could not handle even a fraction of them. Any one method would be straightforward for an expert to code, but a comprehensive setup would be hideously complex. This is why you don't see a mod available now. Verbal descriptions can sound clear and simple, but they must be translated into precise, detailed code with all steps and choices spelled out explicitly.

That makes sense.
I did a little digging & found some forum posts where people were able to create dependent attributes by installing Stock by Attributes AND Dynamic Drop Downs for Stock by Attributes. But... I haven't been able to find any info about whether those modules are compatible with Zen Cart 1.5.0. Anyone know the answer to this?
I e-mailed the original authors of both modules. Hope they respond.