Ability to put the condition based on the asset category flag (CAPEX Item) in the account rule

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We have the requirement to create an accounting rule in TAD which only gets triggered for the CAPEX Item (Item with asset category flag). Our requirement will not be fulfilled by using the Procurement category hierarchy as there can be a scenario in which 2 items one Inventory type and another CAPEX type fall under the same category and in that case, we wouldn't like to trigger that rule for Inventory items.

While inserting the source in the condition I am unable to find the asset category as a source for sub-ledger application Asset/PIM/Purchasing. Is there any other way of making the conditions for the CAPEX item in Accounting Rules?