Alkyl Groups

[Meghna Madhavan 2D]

When indicating what alkyl group is attached to an amine, how do you indicate if there is more than one amine in the chain? For example "N-ethyl-N-methyl-1-propanamine", how would you differentiate between the two amine groups?

[Liz Pecora 1L]

Here is an example of two N in a chain,
H2N-CH2-CH2-CH2-CH2-NH2 1,4-Butandiamine

If there are substituents coming off each N I'm not sure but I'm guessing you would just name one N as a substituent with whatever chain it has attached to it.