Hi,
I'm still trying to wrap my head around why you need multiple server calls... so I will try and provide some insights once I figure that out...
I'm going to use this example, and see if this is something similar to what you are trying to achieve:
You have a "primary" product (maybe this is viewing the detail page, maybe this is on an "add to cart" action) and then you have a few suggested products for "you might also be interested in", or "these are frequently purchased together" type of thing?
If so, why can't you use the products notation to pass all three products at once... and use different events / merchandising evars to distinguish the "primary" viewed/interacted with item with the additional suggestions?
This would be a lot better for multiple reasons:
1. The correlation is right there... no need for fancy data stitching
2. Reducing your server calls (and therefore keeping you contract limits contained - less chance of overage charges at the end of the year)
3. More efficient coding
Unless I am missing something really big here that explains why you need multiple calls.....
In that case, if you set up your eVar with an "Expire After" (this could be set to Visit, or maybe to expire after a specific event is triggered - probably what you would use in this case... ensure that event only triggers in the correct place)
This would allow you to use the "Instance of the eVar" to get the initial call (this limits the data to where the value is set), and use other more "extended" metrics in correlation with the other server calls....
In case you are new to it:
Products Notation: https://experienceleague.adobe.com/docs/analytics/implementation/vars/page-vars/products.html?lang=e...
Merchanding eVars: https://experienceleague.adobe.com/docs/analytics/implementation/vars/page-vars/evar-merchandising.h...
eVar Expiry: https://experienceleague.adobe.com/docs/analytics/admin/admin-tools/conversion-variables/conversion-...
