The house was built in 1950...

I have 2 switches in a dual gang-box.  The switch on the left is a single pole switch which controls 2 lights mounted outside on the front of the house.  The switch on the right is a 3-way switch which controls an outlet in the living room which has a light plugged into it (the other 3-way switch to this light works fine).

The single pole switch has the usual 2 wires connected to it.  The 3-way switch has its usual wires as well (1 black wire to common terminal and 2 travelers).  There is a small black wire connecting the switches.  It is screwed onto the same terminal on the single pole switch in which the constant hot wire is attached to, and "jumping" onto the black common screw of the 3-way switch with another black wire.

Here's my issue:

I'm trying to replace the single pole switch with a timer switch to control the outside lights.  I know that its not code to have 2 wires on a terminal and the way these switches are currently wired, both of them have this issue.  With only 1 constant hot wire coming into the box, I figured the wire was jumped to the 3-way switch to power it, but when I disconnect the other wire and leave the jumped hot wire on the 3-way, the 3-way does not work.

Hope I explained that well enough...any assistance would be greatly appreciated.  Thank you in advance![![enter image description here][1]][1]


  [1]: https://i.sstatic.net/RMP5A.jpg