Using one itunes database across two macs

I currently run a 2010 MBP (500gb hd) at home and on the road and a 2013 Imac (1Tb hd) at work. I have a large lossless itunes library of about 300gb and would like to increase the library further.

My MBP started running slowly and I realised that my iTunes library was choking the whole computer. I started to explore ways to store my library on a remote disk and bought a G drive 1Tb portable drive.

My efforts to carry out the transfer were only partially successful with most of my library transferring but a significant number of tracks displaying the ! sign which means they couldn't be located.

I have also got an Imac at work and what I had hoped to achieve was to have my iTunes database on the 1tb portable drive and use the portable disk on both my MBP and iMac.

Our technical support company are dubious about whether this will work because the local specific itunes library data on each machine will differ and each machine will not operate correctly with the underlying data on the portable drive.

I am not very technical and I am finding it difficult to follow the various posts on this board and elsewhere. Many seem to comment on splitting their library across multiple disks but I cant really seem to get to the bottom of storing my library on one disk and using it across multiple computers.

Is what I am trying to achieve practical?

If it is, can someone point me to an article/post please? Or alternatively could someone explain how I might achieve my goal.

Thanks in a advance for your help.