Custom Fileds Excerpt

[Solti]

Hello, sorry if my question is been answered before, i just cant define my search for what i am trying to do
I have Joomla 2.5.17 and VM 2.0.26d.
I need to add 2 or more custom fields in a product page for example:

A product has 2 custom fields:

1 Field
Size:
Small
Medium
Large

2 Field
Color
Red
Blue
Green

The point is, that the green color is only available for small and medium size. So how can i do that when i choose "Large" size, the "Green" color to disappear or grayed out as unavailable?

[balai]

Use the stockable variants plugin as custom field type