Gmx insert-molecules for adding 4 kinds of different molecules


I want to add four kinds of molecules to my simulation box. Should I use gmx insert-molecules in four steps? In each step, how can I add new molecules in the previous gro file?
Is it possible to use gmx insert-molecules one time and add all the molecules simultaneously?

I will appreciate any help.

With each call of gmx insert-molecules you insert one type molecule, then use the output from that step as the input for the next to insert another type of molecule.

Thank you so much.