Is there a way to break a BOM into multiple before sending it to GTM?

Summary:

Is there a way to break a BOM into multiple before sending it to GTM?

Content (please ensure you mask any confidential information):

Our integration tool has a file size limit of 4MB and BOM size is larger than that. One of the workarounds that we are exploring is to break the BOM into multiple ones before sending it to GTM. Hence we did a test by sending BOM1 and BOM2 to GTM, both with the same Item Structure ID, expecting components under BOM2 will append to existing components in BOM1. Transaction Code tested were IU, UI and RC (managed child were other elements instead of components). However components in BOM2 wiped off existing ones in BOM1.