This is very much depending on your hardware, but most probably for notebooks/netbooks: no.
However, it is common to be able to share the physical input jack for both line-in and microphone input modes. Both modes are related to input, usually. On some desktops I've seen the ability to change the output configuration mode from stereo to 6-channel output to configure the three jacks as output.
To see the options for your sound card I know of the following two options:
Again, this is very much hardware dependent and based on the information in your question there's no way to tell your hardware has this capability or the one you ask for. Just try to see what your options are.