Hi Basil,
Thanks for contacting Syncusion support.
Based on your update you have mentioned that you need to display the child grid as a column in the Grid. In this we are unclear about your exact requirement, so please provide the below details
1. Share the UI representation of your requirement.
2. Please provide more details on your requirement.
By default child grid works based on queryString property and its records are displayed for entire row of parent grid not a specific column. Please refer it below sample.
Please get back to us, if you need any further assistance.
Regards,
Thiyagu S.