Loads to Master data object

If I have created selection packages to load to a master data object for example:

1. Load to 0MAT_PLANT

2. Five packages created filtered by plant range

If I kick off the first package do I need this load to finish before the second package can load into the object i.e. 0MAT_PLANT is locked by the first package or can I load packages in parallel to a master data object? If so how? Thanks