Selro support bundle products (or Kit). Please follow the below steps to create bundle products.
a) Assume you got two products with SKU 'PRODUCT_SKU_1' and 'PRODUCT_SKU_2' and want to create a new bundle product with SKU BUNDLE_SKU_1
b) Please create a new product with the SKU BUNDLE_SKU_1 and set the type to 'Bundle'
c)Please go to 'Bundles' tab and add two products with the SKU 'PRODUCT_SKU_1' and 'PRODUCT_SKU_2' and assign the qty for the bundle. e.g if you want to include 1 of each product into the bundle, please enter the qty 1.
d) Now you can start listing this product to marketplaces or your e-commerce stores and quantity will get automatically sync based on the stock availability on main products.