Item models (1.21.4) Same value for different cases

Hi guys, I have a question
I'm setting up a 1.21.4 item model for my custom item, using a select property that selects by the display_context property.
I, actually, only have two model options, 1 for thirdperson_lefthand/firstperson_lefthand/head and one for all the other display contexts.
e.g.
            {
                "when": "thirdperson_lefthand",
                "model": {...}
            },
            {
                "when": "head",
                "model": {... same model value ...}
            },
...

For the second option, I just put it as fallback value, but for the first one, I had to write the same value (around 60 lines) three times.
Is there some way to move the model value to a external file and then reference it or to merge different cases with same value (my case) into one? 
*Something like * "when": [ "thirdperson_lefthand", .... ] would be cool