Identify multiple instances in a listvar for the same visitor

This one is tricky... 

I assume you are passing the three pieces of info as a value set into your list, like so:

"supplier name 1|123|type a,supplier name 2|555|type b,supplier name 3|127|type a"

So you end up with:

• supplier name 1|123|type a
• supplier name 2|555|type b
• supplier name 3|127|type a

If you have classifications on your list, you could split these into Name, ID, and Type

Now, you could take your Visitor Id dimension, and break it down by your list items, but I don't know if you can create a segment for this...

The problem is that whether you pass 1 value, or multiple values... the instance of the list only counts "1".

Are these being set only when a user subscribes to the supplier? Or as the user adds more or removes suppliers, this tracks the full list of their current state?

I would almost be tempted to change the implementation to using s.products, and create up to three separate numeric metrics.... if you are tracking current state, I would have a metric for it; then I would have one for "adds" and one for "removes"

So let's assume you are using a current state tracking...

I have three suppliers, in my products I would use a dedicated category to denote my usage for "supplier" tracking:

(event1 is current state, event2 is add, event3 is remove, eVar1 is supplier name, eVar2 is supplier id [a duplication of the product identifier - I find this is sometimes easier to use in some cases], eVar3 is type)

"supplier;123;;;event1=1;eVar1=supplier name 1|eVar2=123|eVar3=type a,supplier;555;;;event1=1;eVar1=supplier name 2|eVar2=555|eVar3=type b,supplier;127;;;event1=1;eVar1=supplier name 3|eVar2=127|eVar3=type a"

Now, I have an action to add "supplier name 4"

"supplier;263;;;event2=1;eVar1=supplier name 4|eVar2=263|eVar3=type c"

And another action to remove "supplier name 2"

"supplier;555;;;event3=1;eVar1=supplier name 2|eVar2=555|eVar3=type b"

Basically, on the add / remove actions, I would only pass the one that is being impacted... or you might have the full list of current and the removes like so:

"supplier;123;;;event1=1;eVar1=supplier name 1|eVar2=123|eVar3=type a,supplier;555;;;event1=1;eVar1=supplier name 2|eVar2=555|eVar3=type b,supplier;127;;;event1=1;eVar1=supplier name 3|eVar2=127|eVar3=type a,supplier;263;;;event2=1;eVar1=supplier name 4|eVar2=263|eVar3=type c"

or

"supplier;123;;;event1=1;eVar1=supplier name 1|eVar2=123|eVar3=type a,supplier;555;;;event3=1;eVar1=supplier name 2|eVar2=555|eVar3=type b,supplier;127;;;event1=1;eVar1=supplier name 3|eVar2=127|eVar3=type a,supplier;263;;;event1=1;eVar1=supplier name 4|eVar2=263|eVar3=type c"

In my reporting, if I want to know users who have more than 1 active supplier, I should be able to create a HIT segment

HIT

     event1 is greater than 1

(or use "greater than or equal to 2")

Now of course, every hit is going to count event1, so it won't be a great metric to use on its own... but it can be used with segments to apply context (event1 exists, or on hits to get the concurrent values, etc)