Chart synthetic spreads


Would highly appreciate if you could provide the ability to chart synthetic spreads. Some call it ratios some call it spreads etc.

FOr example in TOS you can plot Bond spreads or butterfly, Long the begning of the curve, neutral the belly of the curve and short the tail of the curve. for eg. in TOS : 5*/ZF-2*/ZN-/ZB, it will plot this spread with ease.

Just need the ability to chart , when it comes to trading this spread, outright individual contracts will be traded, so no change in trading but chart plotting ability required.