If you have many similar filter options, let's say sizes 10, 10.5, 10/11, and Large, you can merge filters in a way that only the size '10' option appears in the filter menu, and once this option is selected products with sizes 10.5, 10/11, and Large will also be shown.
This can be used in a number of ways, but the two most common are:
Grouping colors or sizes that are similar. For example, let us say you have a number of variations of colors that should all map to a single 'Blue' filter, such as 'Navy', 'Sky Blue', 'Baby Blue', and so on. You can associate each one of these alternative tags to the 'Blue' filter, so when a user clicks on 'Blue' all the blue variations show up. When setting this up you will want to check 'Hide the matching filters', this will hide any of the alias filters, such as 'Navy', so it won't show as a filter. This feature works with the Variant Tagger, allowing you to see all of your color, size, and other variant options and then map them to a single filter.
Creating 'parent' filters. You can create a new parent filter that is an aggregation or sum of all of the alias or child filters. This is an easy way to create a top-level set of filters that contain a number of sub-filters that map directly to each other. When used in combination with the Conditional Filters system it allows you to create a set of sub-filters that only show when you select the top-level filter, and where the top-level filter contains all of the sub-filter products exactly.
Note that for each tag alias you should expect each matching product to be tagged with both tags - the alias tag and the parent filter handle/tag. So in the example above for colors, a Navy product would be tagged with both 'navy' and 'blue', or if using tag prefixes 'color-navy' and 'color-blue'.
To merge filters, click the '+' icon next to the filter option and then select filters/tags you want to merge into it.
Note, in the window where you select filters to merge, there is "Hide the matching filters" option at the bottom - this should be checked if you want merged filters (sizes 10.5, 10/11, Large, etc.) to be hidden.
TLDR; here is a video guide on merging filters:
Another example of how to merge colors into primary colors. This is much the same as the sizes, above. You may, however, want to create new filters for each of your 'primary' colors, if they do not exist yet. Click on 'Add Filters', then select 'Tags', and type in your primary color names. You can then merge your other color filters into the new primary color tags that were just created.
If you have any additional questions, please contact support through the live chat in the app, or at firstname.lastname@example.org