VB6 - Reading/Writing to file over network

I have two programs running which decode data from aircraft, each program writes to a .csv file the first time a particular aircraft is heard.

The programs run on different PCs on a LAN - is there any way I can Read/Write to a single .csv file over the LAN to save data, rather than having to merge the 2 files manually?

i.e. how do I open a file to read/write over a LAN in VB6 - I have the E: drive on the 2nd machine set up as a mapped network Z: drive on the first PC, but Z: does not appear in a drive list box on the 1st machine.

Mike