Not how it works bud. You can’t create a claim there were dissident groups and them ask me to disprove your claim. Mainstream history proves there were no dissident groups at that time that were of any significance so as to be mentioned in the historical record. Gussied Cassava are proto protestants. Moreover your little gotcha question proves that the view that Mary was not always a virgen is a dissident position ie not accepted by the group.
I asked you for proof to substantiate your claim.
It is clear you cannot prove that so your claim is invalidated.
In reality the dissident group is the roman catholic church as it's teaching is in opposition to the Word.
The Greek proves she was a virgin until Christ was born. After that, the text notes Joseph and Mary had children....if one reads it in context. The catholic, or anyone else, has the burden to disprove the original language.
If you don't want to believe that I cannot help that.