Overview
This article relates to the Connect: CERM integration only.
When several basket lines share the same External ID (for example, multiple versions of the same print job), you often want to price them as a single bulk quantity instead of line-by-line.
The Aggregate quantities mode setting in the Connect: CERM plug-in lets you do exactly that:
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All lines with the same identifier are grouped.
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A single “get price” call is sent to CERM for the total quantity/number of versions.
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The returned unit price is cached and reused for every grouped item, so there is no performance penalty.
Heads-up:
• If Always retrieve price from calculation is enabled, the calculation ID (not the product ID) is used as the grouping key.
• A follow-up enhancement is planned for baskets that mix versioned and non-versioned products sharing the same External ID. For now, only items of the same type (all versioned or all non-versioned) are aggregated.
Key Settings
Setting |
Location |
What it does |
When to change it |
Aggregate quantities mode • No aggregate (default) • Same Connect ID |
Admin ➜ Configuration ➜ Plugins ➜ Connect: CERM [Configure] |
• No aggregate: keeps legacy behaviour—each basket line is priced separately.• Same Connect ID: groups lines that share an External ID (or calculation ID) and prices them once for their combined quantity. |
Enable Same Connect ID when you need bulk pricing across multiple basket lines of the same job or SKU. |
Always Use Calculation Price |
Admin ➜ Configuration ➜ Plugins ➜ Connect: CERM [Configure] |
Tells the plug-in to use the calculation-level price. When on, aggregation groups by calculation ID instead of product ID. |
Turn on if your pricing logic lives in CERM calculations rather than product records. |

Use Cases
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Versioned print jobs
An order contains four versions of a leaflet (same External ID, different artwork). With aggregation, the system sends one request for the total quantity and receives a single unit price that applies to all four lines.
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Bulk re-orders split into lines
A buyer duplicates last month’s order, creating separate basket lines for each colour way but keeping the same SKU. Aggregation ensures the customer gets the correct bulk discount.
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Performance with large baskets
High-volume web-to-print storefronts often exceed 100 basket lines. Aggregating identical External IDs reduces the number of MIS calls and keeps page load times low.
Step-by-Step Implementation Guide
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Open CERM plug-in settings
Admin ➜ Configuration ➜ Plugins ➜ Connect: CERM [Configure]
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Locate Aggregate quantities mode
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Select “Same Connect ID”
• Click Save.
• If you rely on calculation-based pricing, also enable Always Use Calculation Price.
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Verify the result
Recommended test sequence
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Add two (or more) products that share the same External ID to the basket—ensure their combined quantity is obvious (e.g., 3 × 225 = 675).
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Check the unit price returned on the basket page and at checkout; it should reflect the total quantity, not each line’s quantity.
By enabling Aggregate quantities mode, you guarantee accurate bulk pricing, reduce API traffic, and offer a smoother checkout experience—especially for complex, version-heavy orders.