im actually training to be a chartered electronic engineer...so i should prolly know this...but i dont haha...heres my question:

My stereo has phono inputs which i use for connecting to my mixer...but i also connect my computer's soundcard to these inputs as well. The problem is that i have to keep taking out a set of phono leads and putting in the other and this gets annoying...so i was wondering i could somehow merge the two wires (computer's and mixer's) together into one and keep this plugged into my stereo so i can use both at once. Would this actually work or will i blow up my uni dorm if i try this? (im guessing that the resistance/current/etc would change in the wire or something )

Cheers