group of repeated custom field for each product.

hi
i want added a repeated group of custom field (or you can imagine repeated set of fields) to each product . for example:
product 1:
set 1 {custom field A1 custom field A2 custom field A3}
set 2 {custom field A1 custom field A2 custom field A3}

product 2:
set 1 {custom field A1 custom field A2 custom field A3}
set 2 {custom field A1 custom field A2 custom field A3}
set 3 {custom field A1 custom field A2 custom field A3}
set 4 {custom field A1 custom field A2 custom field A3}

product 3:
set 1 {custom field A1 custom field A2 custom field A3}


how to do it? In fact, the number of sets of fields is determined based on the opinion of the person (admin of site ) who creates the product.
is it possible with hikashop? must use characteristics or custom field for my need which is better?

in my case i want sell template.
each template has some layout. each layout has layout preview and layout file and some other attribute.
template means product in hikashop
and layout preview means hika ajax image custom field A1
and layout file means hika ajax file custom field A2
and ...

some of template has 2 layout and some of template has 7 layout. and as i say in above each layout has some attribute.
after customer buy template, can download layout files but before buy template only can see layout preview.
something such as "subform" Joomla field type .